Add tests for initial settings frames being bad

Add working tests for httpcli

Update README.md

Get internal documentation generated in the right place

Don't build codegen in grpc/java dockerfile

Set up Node, Python, and Ruby environment in Jenkins slave.

Fix podspec of tests, sample and README

Set up Node, Python, and Ruby environment in Jenkins slave. Made other minor changes to make those work

Fix C# test access violation exception on Windows

Fix gRPC.podspec to pass pod spec lint

- Relax protobuf requirement to alpha version
- Suppress warnings for GRPCClient
- Fix headers search path
- Document hacks.

Grpc ruby fix extconf rb

Enable runtime configuration of tracers

Removing an assert on chand->security_connector->auth_context.

  Add ability to override default thread pool

Some compilers don't like C99.

Expose gpr_asprintf and gpr_strdup

Fix jenkins build on windows