Merge github.com:grpc/grpc into we-dont-need-no-backup

Makefile

include/grpc++/channel_arguments.h

include/grpc/compression.h

include/grpc/grpc.h

src/core/channel/channel_args.c

src/core/channel/channel_args.h

src/core/compression/algorithm.c

src/cpp/client/channel_arguments.cc

src/objective-c/GRPCClient/GRPCCall.m

src/ruby/.rspec

src/ruby/spec/spec_helper.rb

templates/Makefile.template

tools/jenkins/grpc_jenkins_slave/Dockerfile

tools/jenkins/run_jenkins.sh