Merge github.com:grpc/grpc into now-i-get-to-show-it-to-EVERYBODY

Makefile

gRPC.podspec

include/grpc++/channel_arguments.h

include/grpc++/client_context.h

include/grpc/grpc.h

src/compiler/objective_c_generator.cc

src/compiler/objective_c_plugin.cc

src/cpp/client/channel_arguments.cc

src/cpp/client/client_context.cc

src/csharp/Grpc.Auth/GoogleCredential.cs

...p/Grpc.Core.Tests/Internal/MetadataArraySafeHandleTest.cs

...rp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj

src/csharp/Grpc.IntegrationTesting/InteropClient.cs

src/node/README.md

src/node/examples/math_server.js

src/node/examples/route_guide_server.js

src/node/examples/stock_server.js

src/node/index.js

src/node/interop/interop_server.js

src/node/src/server.js