preserves title after update_table_data

Just caught that the title was also getting squashed when calling `update_table_data`. I refactored the existing method to preserve the title, and moved that and and the bind_submit method into an `after_setup` method.

```ruby
def after_setup
  self.title = self.class.send(:get_title) # Formotion kills the title when you request tableView.
  self.bind_submit # bind submit action after populating table data
end
```

 I would have liked to move `bind_submit` into the `screen_setup` method for clarity, and because it already sets the title, but since that's actually a hook into `ScreenModule#on_create` it gets called before a form exists and is thus useless for initial setup. 

It's also worth noting that `screen_setup` is basically worthless here because simply calling `tableView` kills what it does anyway.

```ruby
def screen_setup
  # killed by formotion_screen.rb#18  s.tableView.allowsSelectionDuringEditing = true
  self.title = self.class.send(:get_title)
end
```