Merge github.com:grpc/grpc into metadata_filter

CMakeLists.txt

Makefile

binding.gyp

build.yaml

package.json

src/core/ext/census/tracing.c

src/node/ext/completion_queue.h

src/node/ext/completion_queue_threadpool.cc

src/node/ext/completion_queue_uv.cc

src/node/test/surface_test.js

src/php/bin/generate_proto_php.sh

src/php/lib/Grpc/BaseStub.php

templates/CMakeLists.txt.template

templates/Makefile.template

templates/binding.gyp.template

templates/package.json.template

...tools/dockerfile/test/node_jessie_x64/Dockerfile.template

templates/vsprojects/grpc.sln.template

test/core/memory_usage/client.c

test/core/memory_usage/memory_usage_test.c