remove unused imports
pyflakes fixes
WIP new 'make travis'

- install cython from ppa
- add python 3.3
- do not install web.py on 3.3
- run linters first to abort broken builds early
- do not test psycopg2_pool.py

new make commands:
 - make whitespace
 - make pep8
 - make pyflakes
 - make lint    # runs all of the above
 - make travis  # runs on travis