Merge github.com:grpc/grpc into bm_perf

BUILD

CMakeLists.txt

Makefile

binding.gyp

build.yaml

cmake/msvc_static_runtime.cmake

composer.json

config.m4

doc/PROTOCOL-WEB.md

doc/environment_variables.md

examples/csharp/helloworld/generate_protos.bat

examples/php/composer.json

examples/php/greeter_client.php

examples/php/helloworld.pb.php

examples/php/helloworld.php

examples/php/helloworld_grpc_pb.php

examples/php/route_guide/route_guide.pb.php

examples/php/route_guide/route_guide.php

examples/php/route_guide/route_guide_client.php

examples/php/route_guide/route_guide_grpc_pb.php