Merge branch 'master' into generic_qps

Makefile

binding.gyp

package.json

src/core/census/initialize.c

src/node/ext/byte_buffer.cc

src/node/index.js

src/node/src/client.js

src/node/src/credentials.js

src/node/src/grpc_extension.js

src/node/src/metadata.js

src/node/src/server.js

src/node/test/call_test.js

src/node/test/channel_test.js

src/node/test/constant_test.js

src/node/test/end_to_end_test.js

src/node/test/server_test.js

src/node/test/surface_test.js

src/ruby/ext/grpc/rb_call.c

src/ruby/ext/grpc/rb_call_credentials.c

src/ruby/ext/grpc/rb_event_thread.c