Error Handling!

Added the SVProgressHUD pod (via Github, copy folder to project folder)
to views with UITableViews (controllers and otherwise). This implements
a spinner so that when users are brought to the tableView, the user
cannot interact with the view until the load is completed.

Otherwise, the user can try to interact with the UITableViewCells (like
the ListingTableViewController cells) and the Parse query is still
loading the data (array is empty till loadData() is completed).

Also, added a single-touch gesture to views that are editable vis-a-vis
UITextField, UITextView, etc. to dismiss the keyboard
(‘self.view.endEditing(true)’).