Merge github.com:grpc/grpc into we-have-better-methods-now

BUILD

CMakeLists.txt

Makefile

build.yaml

...e/grpc++/ext/health_check_service_server_builder_option.h

include/grpc++/health_check_service_interface.h

include/grpc++/server.h

src/cpp/server/health/default_health_check_service.cc

src/cpp/server/health/default_health_check_service.h

src/cpp/server/health/health.pb.c

src/cpp/server/health/health.pb.h

src/cpp/server/health/health_check_service.cc

...rver/health/health_check_service_server_builder_option.cc

src/cpp/server/server_cc.cc

src/proto/grpc/health/v1/health.options

test/cpp/end2end/health_service_end2end_test.cc

tools/distrib/check_copyright.py

tools/doxygen/Doxyfile.c++

tools/doxygen/Doxyfile.c++.internal

tools/run_tests/generated/sources_and_headers.json