Backing up via Dropbox ever 6 hours (if backup.py is running of course). Needs environmental variables set for DROPBOX_APP_KEY, DROPBOX_APP_SECRET, and DROPBOX_APP_TOKEN. Probably will explode and rain hellfire down if running and it tries to backup something other than a SQLite db.

Closes #3
Merge pull request #13 from abkfenris/dropbox-backup

Dropbox backup