Set more build-flags in `setup.py`s

Skip exit_test until flake is fixed

PHP: fix interop tests breakage

php: prepare for GA release

Removes MinGW flags from various build scripts, since they're now set in
our `setup.py`s by default. Also removes the arguments for the
extensions in grpcio's setup.py; that function was already accessing
globals anyway, might as well go whole-hog.

Retrying: Make the testing scripts executable on Python 3.x

Add dockerfile for pyenv and modify run_tests.py to include py35 and py36

Automatic v1.0.x -> master upmerge

Distribute ProtoC and the plugin as pods

Fix cygrpc test

Add API to get C slice from C++ Slice.

Add src/compiler to clang-formatting pass

Add special methods to generated Python docs

This should make Travis only test the last commit of every PR.

Initialize variable.

Use test roots.pem in test - cherry-picking for v1.0.x

Upmerge 0.15 -> 1.0

This is for https://github.com/grpc/grpc/pull/6737 when
start_batch will no longer put data on the wire

Use test roots.pem in test

Patch spawn for Python 'unix' compilers instead of link

Fallback to generating files if not generated

Removed early adopter code

Also removes an old-now-spurious `make` invocation from the docgen.py
helper script.

Conflicts:
	.gitmodules
	gRPC.podspec

gRPC.podspec shouldn't be a template anymore.