Progress towards mdstr elimination

BUILD

CMakeLists.txt

Makefile

binding.gyp

build.yaml

config.m4

gRPC-Core.podspec

grpc.def

grpc.gemspec

include/grpc/compression.h

include/grpc/slice.h

package.xml

src/core/ext/client_channel/client_channel.c

src/core/ext/client_channel/subchannel.c

src/core/ext/client_channel/subchannel.h

src/core/ext/lb_policy/grpclb/grpclb.c

src/core/ext/transport/chttp2/transport/bin_decoder.c

src/core/ext/transport/chttp2/transport/hpack_encoder.h

src/core/ext/transport/chttp2/transport/hpack_parser.c

src/core/ext/transport/chttp2/transport/parsing.c