update_table_data should also update the search table if the user is searching

If the user is searching and `update_table_data` is called, make sure to refresh the searching table view too!

For instance, I have actions on my cells that change the content when tapped. I search the table and tap a searched cell and the cell never updates its content. If I change the search, it will update.

This PR fixes the issue so that the data is reloaded and the search results are updated properly.

The `PM::TableScreen` `searchable` specs are a bit light and this would be a pretty intense test. We're not even testing the actual functionality of the searching, so instead, I updated the `TableScreenSearchable` class to show the functionality working. Just initialize that screen in the app delegate and run the app to see it working.

![search_action_update](https://cloud.githubusercontent.com/assets/139261/3176636/416f1bd8-ec07-11e3-9150-b48eea4c47d0.gif)