Added sign in and registration using SQLAlchemy and Flask-User

(Using pre-existing templates)

Also got rid of /patients for now, since that can just be /
Style guide [sez](https://google-styleguide.googlecode.com/svn/trunk/pyguide.html?showone=Whitespace#Whitespace): "Don't use spaces around the '=' sign when used to indicate a keyword argument or a default parameter value."