Omit test/__init__.py from coverage, it never gets run
gitignore more files
move the pycrypto imports inside the functions

This way we can get rid of the pycrypto hard-requirement, till those
functions are actually used in the webapp
Packaging updates:

- Add more static files in MANIFEST.in and setup.py
- Categorize the dependencies in setup.py
- Remove non-hard dependencies from requirements.txt