Lotw web import

Solution for magicbug/Cloudlog#127 -- Database schema has changed: two more fields added to users table; edit user view and user model changed to get and set user login for LoTW. Config file adds URLs for ARRL LoTW web services, as well as a specification as to whether QSLs received from LoTW are marked as Y or V. Feedback on this would be appreciated. I'm not sure how migration works yet... if someone has a current install, how do the new fields get into the DB and new items in config get put there?