Begin core componentization

Moving grpc_pick_unused_port_of_die before creating a deadline.

Added generic service client and server to Node perf tests

Properly set server payload config in QPS tests

Update clang-format to 3.8

Add scripts for creating performance worker VMs

Change c++_codegen_lib from build: protoc to build: all

fixes to tests for py2/3 syntax compatibility

Don't check read_info for writes