forms: Removed club field from registration form

This caused much confusion because people didn't know how to add their
own club to the list upon registration so they didn't register. Now we let
them register without a club and discover the proper club change form
later.
Merge pull request #188 from Turbo87/clubless-registration

forms: Removed club field from registration form
views/user: Fixed recover_password() method
model/event: Import cleanup
views: Import cleanup
flake8: Added "# noqa" lines to __init__.py files

Ignore "unused import" warnings in these files
Added flake8 to requirements.txt
setup.cfg: Add project-wide flake8 configuration
tests: Replaced PEP8 test with flake8 test
scripts: Import cleanup
scripts: Added "# noqa" to side-effect imports
Merge pull request #189 from Turbo87/flake8

Flake8 support