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, 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. I might have made use of the `on_init` method here as well, but since I need to repeat the process at the end of `update_table_data` I didn't feel like that made sense either.