py.test respects env vars PYTEST_{VERBOSE,EXITFIRST,NOCAPTURE,TBNATIVE}
install.sh also install flake8
flake8 ignore yacctab/lextab (transitional until pycparser fix)
tox.ini: pycparser has moved to GitHub
Update pycparser minimum required revision after move to GitHub
Remove distribute from tox deps
Add mpi4py to tox.ini deps
Add README instructions for configuring pyopencl
Update pycuda minimum requirement to 2013.1
Merge pull request #191 from OP2/misc-fixes

A number of small fixes previously overlooked.

The unit test respect some environment variables
that modify py.test invocation:
PYTEST_VERBOSE adds -v
PYTEST_EXITFIRST adds -x
PYTEST_NOCAPTURE adds -s
PYTEST_TBNATIVE adds --tb=native

These are used by buildbot.