Updated selectable table so it works with Symphony 2.4

This may have been an issue in earlier versions, but it was definitely an issue in 2.4. Tables were no longer selectable (requiring more than just the class), changing the way the table was built fixed it.
New release for 2.4 fix
Merge pull request #4 from nathanhornby/master

Updated selectable table so it works with Symphony 2.4