In 6e7d0890 we added better travis continuous integration tests. This is nice,
but has two problems:
- We run only a subset of interesting tests.
- The travis builds can take hours to give us back results (especially on OS X).
This adds scripts/gen_run_tests.py, and its output, run_tests.sh, which builds
and runs a larger portion of possible configurations on the local machine.
While a travis run takes several hours to complete , I can run these scripts on
my (OS X) latop and (Linux) devserve, and get a more exhaustive set of results
back in around 10 minutes.
