-) You can't assume bash is installed. Scripts needs to be cleaned out of bashisms.
-) You can't assume python is in /usr/bin. Use env instead.
-) AF_INET is in sys/socket.h
-) Added port_platform's basic structure for FreeBSD, based off Darwin.
-) FreeBSD doesn't have and doesn't need libdl for OpenSSL.

Allows:
- running python tests in parallel
- clearer Travis output
- subjects each python test to the five minute run_tests timeout,
  instead of ALL the tests to the five minute timeout
- easier benchmarking of which tests are slow

Allows run_tests to focus on one particular test if necessary.
Useful in combination with runs_per_test.

And reflects the C++ API in ServerBuilder.

This allows caching results with --runs_per_test.

Otherwise the tests just stop once they succeed, or don't even run at
all if they passed in a previous run.

I tried actually doing a build on my home desktop, and none of these
run with python 3.3, which is /usr/bin/python on my home desktop.

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

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.