Mongoose 7.7

• Added an experimental embedded TCP/IP stack
• Added MG_ARCH_RTX Keil MDK RTX support
• Added MG_ARCH_NEWLIB
• Added MG_ARCH_TIRTOS TI RTOS support
• Added Keil MDK tutorial
• Added TI RTOS example
• Added Zephyr support and 4 TLS-enabled examples
• Enhanced device dashboard example
• Changed mg_hexdump() to use logging instead of malloc-ing hex string
• Refactored multithreading API, enabled bidirectional IO
• Fixed TLS buffering issue
• Fixed up / enhanced many util functions
• Fixed MQTT suback handling
• Introduced MG_ENABLE_CUSTOM_MILLIS for custom uptime functions
• Fixed DNS failure handling
• Added more unit tests - for failed auth TLS validation and others
• Added valgrind tests
• Fixed HTTP chunk handling
• Using independed mg_snprintf() routine instead of C lib
• Enhanced docs
• Enhanced fatfs support