converted FieldsTableView to a map view
added polyline core data object; added display for polyline on map
added edit button to map; Farm can be created and stored into core data, and automatically reloaded
added center pin for add field mode; added cancel button to cancel add field mode
added annotation pins for farm center
fixed addition of fields to farms; fixed reload of map after adding a field
Merge pull request #8 from mitrenegade/map

Map