1.6.2 - add strXxx_T() functions for template programming; fix PrintStr::flush() for ESP32 on PlatformIO

• 1.6.2 (2023-06-25)
  • Add tstrings.h which adds various strxxx_T() overloaded functions
    which take either a const char* or a const __FlashStringHelper*
    parameter.
    • Allows writing C++ template code which is agnostic to whether the
      string argument is in normal memory or flash memory. The compiler will
      select the specific implementation automatically at compile-time.
  • PrintStr.h
    • Add special exception for ESP32 on PlatformIO which seems to be
      stuck using the ESP32 Core from 1.x, which means that its
      Print::flush() is non-virtual instead of virtual (fixed in v2.0.3).
    • See PR#28.

1.6.1 - add additional KString() constructors, fixing backwards compatible breakage

• 1.6.1 (2023-06-09)
  • Fix backwards compatibility breakage in KString() constructor.
    • v1.5.2 supported only:
      • KString(cstring, cstring)
      • KString(flash, cstring)
    • v1.6.0 changed to support only (in prep for next version of AceTime):
      • KString(cstring, cstring)
      • KString(flash, flash)
      • which breaks old version of AceTime v2.2.3
    • v1.6.1 adds all remaining combinations:
      • KString(flash, cstring)
      • KString(cstring, flash)
    • Now works for both old and new AceTime versions.

1.6.0 - more PROGMEM support in KString; add SAMD21, SAMD51 boards to Tier 1

• 1.6.0 (2023-06-08)
  • Add overloaded flash string versions of copyReplaceChar() and
    copyReplaceString() which accept __FlashStringHelper* pointers in the
    source string parameters.
  • Support keywords[] in PROGMEM in KString class.
  • Update supported boards and tiers
    • Add SAMD21 and SAMD51 boards to Tier 1
      • Add 2 SAMD boards from 2 different companies, to test their
        Arduino Core software:
        • Seeeduino XIAO M0 (SAMD21 48MHz ARM Cortex-M0+)
        • Adafruit ItsyBitsy M4 (SAMD51 120MHz ARM Cortex-M4)
      • SAMD21 and SAMD51 boards are back in Tier 1, as long as they use
        the traditional Arduino API instead of the new
        Arduino-Core.
      • Fortunately most third party SAMD21 and SAMD51 boards continue to
        use the traditional Arduino API.
    • Move Teensy 3.2 to Tier 2
      • This board is entering end-of-life.
      • As well, the Teensyduino environment integrates with the Arduino
        IDE and CLI in a way that's different than all other third-party
        Arduino boards. Some of my automation scripts do not work with
        Teensyduino, so it becomes very time consuming to test the Teensy
        boards.
      • All Teensy boards are now in Tier 2 ("Should work but not tested
        often").

v1.5.2 - mark PrintStr::flush() as override on most platforms; upgrade tool chain

• 1.5.2 (2022-09-22)
  • Change hashDjb2(const char*) to be an inlined function instead of
    simply delegating to the template version.
    • Increases type-safety because passing an incorrect array (e.g.
      uint16_t[]) would compile without any errors, and probably not what
      the user intended since the hash function expects a NUL-terminated
      string.
  • Mark PrintStr::flush() as override.
    • The STM32 and ESP32 platforms have finally fixed their implementation
      of Print::flush() to be virtual, consistent with other Arduino
      platforms.
    • Make exception for ATTinyCore, which does not implement a
      Print::flush().
  • Upgrade tool chain
    • Upgrade Arduino CLI from 0.20.2 to 0.27.1.
    • Upgrade Arduino AVR Core from 1.8.4 to 1.8.5.
    • Upgrade STM32 Core from 2.2.0 to 2.3.0.
    • Upgrade ESP32 Core from 2.0.2 to 2.0.5.
    • Upgrade Teensyduino from 1.56 to 1.57.

v1.5.1 - change signature of backslashXEncode() and backslashXDecode() slightly

• 1.5.1 (2022-02-25)
  • Breaking Change API of
    backslash_x_encoding.h slightly so that the
    status is returned and the written number of bytes is returned through
    a pointer to an out-parameter.
    • Turns out the more common case is to check the status, and
      ignore the written, so the written pointer can now be nullptr
      if the calling code wishes to ignore it.
    • This is technically a breaking change, but the backslashXEncode()
      and backslashXDecode() methods were just added, but I'm going to
      consider this to be a "quick fix", and increment only the minor
      version number.

v1.5.0 - upgrade tool chain; add backslashXEncode() and backslashXDecode()

• 1.5.0 (2022-02-17)
  • Expose byteToHexChar() and hexCharToByte() utility functions from
    url_encoding.h. They became useful in backslash_x_encoding.h.
  • Add backslash_x_encoding.h which provides
    backslashXEncode() that encodes non-printable ASCII characters to \xHH
    form and backslashXDecode() to decode back.
  • Upgrade tool chain:
    • Upgrade Arduino IDE from 1.8.16 to 1.8.19.
    • Upgrade Arduino CLI from 0.19.2 to 0.20.2.
    • Upgrade Arduino AVR Core from 1.8.3 to 1.8.4.
    • Upgrade STM32 Core from 2.0.0 to 2.2.0.
    • Upgrade ESP32 Core from 1.0.6 to 2.0.2.
    • Upgrade Teensyduino from 1.55 to 1.56.
  • Downgrade SAMD21 boards to new "Tier 3: May work but unsupported" since I
    can no longer upload to my SAMD21 boards with the current tool chain.

v1.4.7 - add KString::compareTo(const KString&); upgrade tool chain

• 1.4.7 (2021-11-04)
  • Add KString::compareTo(KString&) using a KStringIterator
    • Supports a single level of fragment nesting (i.e. a compression
      fragment cannot contain another fragment).
    • Needed to implement ZoneSorter classes in AceTime.
  • Upgrade tool chain:
    • Upgrade Arduino IDE from 1.8.13 to 1.8.16.
    • Upgrade Arduino CLI from 0.14.0 to 0.19.2
    • Upgrade SparkFun SAMD Core from 1.8.3 to 1.8.5.
    • Upgrade ESP8266 Core from 2.7.4 to 3.0.2.
    • Upgrade Teensyduino from 1.53 to 1.55.

v1.4.6 - GenericStats, isReverseSorted(), upgrade STM32duino to 2.0.0, upgrade SparkFun SAMD to 1.8.3

• 1.4.6 (2021-08-05)
  • Upgrade STM32duino Core from 1.9.0 to 2.0.0.
    • MemoryBenchmark: Flash usage increases by 2.3kB across the board, but
      static RAM goes down by 250 bytes. Very little change to AceCommon
      code itself.
    • AutoBenchmark: No change.
  • Upgrade SparkFun SAMD Core from 1.8.1 to 1.8.3.
    • No change observed in MemoryBenchmark or AutoBenchmark.
  • Add print_utils/PrintIntAsFloat.h with printUint16AsFloat3To() and
    printUint32AsFloat3To().
    • Divides the provided value by 1000, then prints the result as a
      floating point number to 3 decimal places.
    • Does not use floating point operations to be friendly on 8-bit
      processors.
  • Add GenericStats<T>, a templatized version of TimingStats.
  • Update MemoryBenchmark
    • Add memory usage for String, to provide a better comparison for
      PrintStr<N> and PrintStrN.
    • String consumes about 1000 more flash bytes compared to PrintStr.
    • PrintStrN consumes about 600 more flash bytes compared to PrintStr
      because it pulls in malloc() and free().
    • Add memory usage for isSorted().
  • Add isReverseSorted() and isReversedSortedByKey(). Analogous to
    isSorted() and isSortedByKey().

v1.4.5 - optimize decToHex() for specific platforms; add PrintStr::cstr() alternative for getCstr()

• 1.4.5 (2021-04-26)
  • Create more generic examples/AutoBenchmark program which replaces
    examples/Udiv1000.
  • Activate
    GitHub Discussions.
  • Add decToHexDivOnly() and decToHexDivMod() to AutoBenchmark, and
    update decToHex() to automatically select the faster one. On AVR,
    decToHexDivMod() seems to be 2 clock cycles (125 ns) faster. But on
    32-bit processors, decToHexDivOnly() is 2X faster on those without
    hardware divide (e.g. SAMD21, ESP8266), and 10-20% faster on processors
    with hardware divide (e.g. STM32, ESP32, Teensy 3.2).
  • Prevent overflow of uint16_t when calculating exponential decay average.
  • Add PrintStrBase::cstr() as a shorter, more convenient version of
    PrintStrBase::getCstr(). Retain getCstr() for backwards compatibility.
  • Upgrade to ESP32 Core v1.0.6 and regenerate MemoryBenchmark and
    AutoBenchmark.

v1.4.4 - add copyReplaceXxx(), printReplaceXxxTo(), FlashString class

• 1.4.4
  • Add copyReplaceChar() and copyReplaceString() functions. Extracted
    from AceTime library.
  • Add printReplaceCharTo() and printReplaceStringTo() functions.
  • Add examples/MemoryBenchmark to track the
    flash sizes of various components within this library.
  • Add FlashString class which is a very thin-wrapper around a
    const __FlashStringHelper* pointer, to make it look and act like a
    normal const char* pointer.
    • Solves code duplication problem when writing functions that need to
      support both c-strings and f-strings.
    • First write the function against a generic T type that is
      assumed to be a type that acts like a const char*. Use this for a
      c-string.
    • Second write a template specialization that takes a const __FlashStringHelper*, wraps the pointer into a FlashString,
      and then forwards the call to the generic template function.