Added ID column to games list, Made a way to select columns that are displayed

Added a column labeled "ID" to the main games list and allowed for choosing which columns are displayed.  Personally, when I ripped my games, they ripped as [ID].iso.  It's much easier to match them up with their files it the id is displayed.  
![dolphinidcol](https://cloud.githubusercontent.com/assets/3501739/3085631/61045fc8-e516-11e3-9c1b-e3f0e43e22b3.png)