- properly fail a Read() on a stream if we fail to parse a protobuf
- fix an ordering problem with the chttp2 transport global lock, whereby
  a sequence of two operations could be swapped - this resulted in
  slices being returned to the upper layers in the wrong order,
  corrupting data

Spell out fail fast semantics

Added compression tracer

Fix double delete

Add a shard channel arg to client channel construction

Kill pending python workers on start

ObjC: Add ChannelCredentials to gRPC Call, to let specify a private key for the user

Added node plugin to grpc-tools npm package, updated build_package_node

GRPCHost now has a property channelCreds which is used when creating a GRPCChannel.

Remove Python alpha/early_adopter implementation

Python QPS Tests

C core automatically shares subchannels between channels. Therefore our
multiple channel performance tests were really testing single channel
performance.

Allow additive changes to protos w/o forcing user implementation

Load default roots.pem in Ruby via grpc_set_ssl_roots_override_callback

Load default roots.pem in Node via grpc_set_ssl_roots_override_callback

Make Node servers warn instead of fail when a method is missing a handler

Further lock contention reduction for CHTTP2

Init tracers after plugin registration

Add Windows-specifics to Python docs

Simplify QPS Metrics collection

Better killing of pending QpsWorkers (in single-machine setup).

Interop test cleanup

Add comments to generated C# files.

Provide a function that converts grpc_call_error values into a string

Fix buildgen plugin file comment

Added nullability to service declaration in ObjC

This code has been unsupported for more than six months.