More comment improvements

fix comment about the installation location

clean up some internal path and names

Always run build cleaner

Make run_tests.py respect the run= attribute

Minor changes for compatibility across different compilers

Debian packages libgrpc and libgrpc-dev

Fix TSAN reported error in fd_posix.c

added NuGet package specifications

Defining an installation prefix for grpc's root certs at compilation time.

Make interop server respond to sigint

This will allow the test to shut down cleanly, and avoid failing.

Removing the hardcoded SSL roots.

- Makes 2 tests fail:
  - httpcli_test
  - interop_test

C# renaming of VS projects and some cleanup

These invocation-side values allow users to choose
between synchronous and asynchronous execution of
their RPCs with a single attribute access.

Successful operations were leaking the thread used for expiration
monitoring. This change ensures that the ExpirationManager for the
operation always has its abort() method called when the
TerminationManager for the operation judges the operation to have
terminated.

remove prod_roots_certs.c

include .m in check_copyright.py

Ensure interop tests are run as part of run_tests

Fix server side large message receiving