Merge github.com:grpc/grpc into cleaner-posix2

.gitignore

.travis.yml

BUILD

INSTALL

Makefile

binding.gyp

build.yaml

config.m4

gRPC.podspec

grpc.gemspec

package.json

package.xml

src/core/client_config/subchannel_index.c

src/core/compression/compression_algorithm.c

src/core/security/b64.c

src/core/security/b64.h

src/core/security/google_default_credentials.c

src/core/security/json_token.c

src/core/security/jwt_verifier.c

src/core/security/security_connector.c