Expand header testing

Expand continuation testing

Expand bad_client to be able to make full requests

Add test for un-resolvable target

Fix encoding for bytes fields in ruby interop client

Expand HPACK decoding test cases

Nuke unused files

Add test of varint encoding for hpack

add test for more plucks than allowed

Merge release-0_12 into master

Improve test coverage for Slice test

Unknown frame test

Add test coverage for gpr_refn() function

Deduplication of health.proto and math.proto

Use updated metadata auth call credentials core API in
Python (and migrate to Cython).

Node benchmark service

Fix string literals to hit the cases theyre supposed to

Fix windows build

add test for pluck after shutdown