Invalid responses Bug #3283

The issue was caused by the UITableView subclass (NUSectionTVC) being refreshed before a cell's textField had resigned it's first responder. The result was that when the tableView was refreshed, the textField's didFinishEditing was being called which in turn called a method for an empty response to be created and saved to the persistent store.

The issue was resolved by creating a notification to alert any open textFields to resign it's first responder before the tableView was refreshed. A test was written to confirm that this worked.