Merge branch 'master' of https://github.com/grpc/grpc into to-grpc-err-is-human

.pylintrc

CMakeLists.txt

Makefile

bazel/cc_grpc_library.bzl

bazel/generate_cc.bzl

bazel/grpc_build_system.bzl

binding.gyp

build.yaml

composer.json

doc/PROTOCOL-WEB.md

doc/server_side_auth.md

examples/php/composer.json

gRPC-Core.podspec

include/grpc/impl/codegen/sync.h

package.xml

requirements.txt

setup.py

src/compiler/cpp_generator.cc

src/core/ext/client_channel/client_channel_plugin.c

src/core/ext/client_channel/http_proxy.c