users/constants.py: pep8 fixes.
Set titles in templates.
Switch to python3.

Conflicts:
	run.py
Add login, logout, and register links to nav.
Remove whitespace in decorators.py.
Use Flask-Login to handle login.
users/decorators.py: Delete.

login_required is now handled in Flask-Login.
PEP8: Removed unused import and add whitespace.