Merge branch 'master' of https://github.com/grpc/grpc into tracing-overhaul

BUILD

CMakeLists.txt

INSTALL.md

Makefile

binding.gyp

build.yaml

config.w32

doc/environment_variables.md

package.json

src/compiler/objective_c_generator_helpers.h

src/compiler/objective_c_plugin.cc

src/csharp/Grpc.Core.Tests/ServerTest.cs

src/csharp/Grpc.Core/Server.cs

src/csharp/ext/grpc_csharp_ext.c

src/node/src/grpc_extension.js

src/node/test/surface_test.js

src/objective-c/tests/PluginTest/imported-with-dash.proto

src/objective-c/tests/PluginTest/test-dash-filename.proto

src/objective-c/tests/build_tests.sh

src/objective-c/tests/run_tests.sh