Also speed up a test, and disable some rarely touched but long running tests

Update suppressions file

Added ruby tests to run_tests.py

Fix conditional inclusion of grpc_csharp_ext.dll

Removing private protobuf header inclusion.

Allow starting from non-root directory

Drop fixed port from python_plugin_test

Increment 'try' variable

Added C# interop server

Added useful information and links to Node's package.json