Added support for sending metadata from clients.

Using cc and c++ instead of gcc and g++.

Removing src/core/security/roots.pem

I believe it was introduced by mistake here:
https://github.com/grpc/grpc/commit/3f1e69668642c42372b2e54c502458dc8dbba1bf

Reenable a disabled test method

Add at CANCELLATION back-to-front ticket kind

This addresses issue #752.

Use distinct enums for distinct ticket types

Python refactoring

Fixed argument types in setup.py

Since enums are themselves iterable there's no need to maintain a list
of the elements of the enum dating from back before the enum when its
values were just independent constants that hung out together.

This refactoring greatly reduces the base-internal use of packet kinds
and will make much simpler a future change distinguishing front-to-back
packet kinds from back-to-front packet kinds.

Anonymous API implementation

Defaulting run_tests to just opt.

Remove dead code

Put back C++ JWTCredentials code and add a test case in interop test.

remove 'else' code, release lock by destructor

Not all systems are equal, and have gcc. However, cc and c++ are more common aliases for the system's compiler.
FreeBSD is an example.

Allowing us to import google::protobuf::int64.

If for any reason, our definition of gpr_int64 is different from the definition of google::protobuf::int64, the virtual override would fail, as this needs to be of the precisely exactly the same type.
That change allows us to use protobuf's int64 definition.

Switched protobufjs dependency to npm package instead of GitHub

Adding support for alternative protobuf libraries.

Add a no_barrier_load atomic operation.