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.
Introduces gen_travis.py, which generates .travis.yml, and updates .travis.yml
to be the generated version.
The travis build matrix approach doesn't play well with mixing and matching
various different environment settings, so we generate every build explicitly,
rather than letting them do it for us.
To avoid abusing travis resources (and save us time waiting for CI results), we
don't test every possible combination of options; we only check up to 2 unusual
settings at a time.
