Clarify the oauth2_auth_token scenario and add the per call credentia…

Increase timeout of tests to remove flakes.

List Objective-C library as alpha.

Clean up handshaking server channels properly

Enabling 32 bits downgrade of our environment.

Replacing echo -e with a more generic system.

remove dead file

Lockfree stack

Added WriteOptions for per-message flags and modified CallOps to use it.

generate_projects.py should make directories.

Create server side auth context lazily

The 'tr' command can actually accept escapes, such as \n.

Nuget versioning simplification

C# health service

Updates the requirements comment before releasing on the release branch

Fixed wrong frame parsing

Fixes for older C++ compilers (remove lambdas, brace init, and nullptr ambiguity)

Get rid of explicit GrpcEnvironment.Initialize

Update homebrew PHP extension location

links interface and gRPC-on-wire implementation

Clang-format of changed files

build. The issue is that gcc below 4.6 require us to explicitly define nullptr,
and our explicit definition allows a potential confusion between
nullptr->unique_ptr<string> and
nullptr->char *->grpc::string->unique_ptr<string>