There may be a way to use third_party's protobuf (and this
may eventually be necessary) but I haven't yet figured out
how to do it correctly. It can happen later.

The source code is moved from src/python to
src/python/src. A setup.py is added at
src/python. The build_python.sh and
run_python.sh scripts are updated to build
and run the Python tests by building a
package and installing it in the developer's
Python 2.7 virtual environment.

Refactor the code a little to make this easier to munge around.

The images seem to have been broken starting with 12e12a39, but the
removal of Maven support from grpc-java also broke them further.

SSH handling no longer uses $HOME as it does not agree with /etc/passwd
in older docker versions[1] and prevented SSH from seeing the config
file.

Some effort was also made to reduce the image sizes by removing
temporary files.

1. https://github.com/docker/docker/issues/2968

refactoring will happen when the commands are final.

Run faster on smaller machines.

Don't watch '.' prefixed files for changes. These files don't typically contribute to builds, and are used as vim temp files.

roots.pem is not added to source control, but is instead saved on GCS.

The func copies roots.pem to docker host, to a location that can referenced by
Dockerfiles using the ADD directive

- the client test gets new, necessary flags

- adds a prod test command that explicitly sets the SSL_CERT_FILE to pick up
certs that the c core can load successfully.

Adding 2 runners to run the test matrix

Use of these tools is dangerous until such time as we can figure out a standardized clang-format version to use everywhere.