Added a tab bar, tinder-style flash cards, updated CB url.
[card helpers] Added functionality to copy couch db data to core data.
[card model] Now maps to core data and has couchdb related properties.
[quiz view controller] Does not manage its own couch connection, changed some ui stuff.
[couch manager] Added.
[main view controller] Uses couchmanager now.
[app delegate] Inits core data and couch manager.