The -r option passed to sed is a GNU sed option for extended regex
evaluation. The -E option evaluates the same option, and is part of the
POSIX standard, meaning this option is available in GNU sed as well as
Apple's BSD variant.

This commit removes the need for users to install gnu-sed on Mac.

This adds a very barebones implementation for a ktor server generator.

This supports metrics and typed locations. All endpoins are stubbed to
return HTTP/1.1 501 Not Implemented.

Options available:

* featureAutoHead
* featureConditionalHeaders
* featureHSTS
* featureCORS
* featureCompression

ktor doesn't seem to explicitly accept oauth flow properties in its
configuration object. This may be a blocker for 'implicit' flow
definitions.

ktor locations are only supported for routes with path/query parameters.
Routes with body or file parameters must be declared with traditional
route api.

This commit also includes lambdas for simplifying processing in
library-based server generator code. As an example, ktor requires
lowercase http methods while spring (a potential future generator)
would require an uppercase such as HttpMethod.GET. It doesn't make sense
to modify these in the operations post-process method because that
format wouldn't be universally desirable.

The lambdas included in the KotlinServerCodegen:
* lowercase: converts all text to lowercase
* uppercase: converts all text to UPPERCASE
* titlecase: converts words (with configurable delim) to Title Case
* indented|indented_8|indented_12|indented_16: these helpers apply the
  same desired indent to all lines of an included fragment's text.

* master: (133 commits)
  add a link to ebook (polish version)
  Add R namespace file (swagger-api#7467)
  Add Spring Petstore samples (async, java8-localdatetime) to CircleCI (swagger-api#7468)
  Revised core team members
  Ada code generator corrected: "=>" instead of "->". Fixes swagger-api#7450 (swagger-api#7456)
  Fixes issue swagger-api#7177 (SpringCodeGen dateLibrary "java8-localdatetime" option is ignored). (swagger-api#7178)
  Issue-7438 Fix that prevents generating interfaces when interfaceOnly is false. (swagger-api#7439)
  swagger-api#7093 - Add maven wrapper (swagger-api#7356)
  [csharp] Support arrays of arrays for properties and models (swagger-api#7400)
  [csharp] Fix ToJson to work with composition and polymorphism (swagger-api#7399)
  [csharp] Reference this.Configuration in client api template (swagger-api#7394)
  [JAX-RS][Spec] Removes throws Exception. (swagger-api#7437)
  Use supportsES6 flag in ts compilation for language typescript-angular (swagger-api#7408)
  Fix 7457: [Ada] wrong order for generated structures in *-models.ads (swagger-api#7462)
  Fix 7459: [Ada] wrong JSON in POST operations (swagger-api#7460)
  [erlang-client] Erlang request utils (swagger-api#7257)
  reenable pushing snapshot to maven repo
  Create CODE_OF_CONDUCT.md
  comment out update to docker image
  deleted unnecessary notes (swagger-api#7454)
  ...

Change `kotlin` to `kotlin-server`

…codegen into ktor-server-initial

* 'ktor-server-initial' of github.com:jimschubert/swagger-codegen:
  Update kotlin-server-petstore.bat