* build only travis-ci branch
* added a vaurien.txt for running full stack integration tests
* added targets in .travis.yml and Makefile to run vaurien fronted
  mysql and redis proxies
* allow the explicit setting of the virtual_env bin path when starting
  ichnaea, but fall back to bin/gunicorn otherwise
added an event listener for connection checkout from the sqlalchemy database pool to discard connections that have gone stale
* added tests for search
* TestSearch will only pass vaurien tests when individual test methods
  are run separately with cleanly restarted proxies