Run tests on travis ci
travis: install requirements and run mailpile-test
travis: don't use requirements.txt
travis: use direct link for GnuPGInterface
travis: drop py2.5 as we can't run self-test there now
travis: make pep8 less strict now
Nose tests, track coverage, don't do pep8 and pyflakes
tests: TestUI: better log messages verification
tests: updated search tests