Shopping tooltip

This adds the tooltip from #2121 to the shopping gamestate and it can be used with any vender.  This pull does rely heavily on the code from #2121

![screen shot 2014-07-20 at 12 22 02 am](https://cloud.githubusercontent.com/assets/4028391/3637901/18e42196-1028-11e4-9b49-f940904cbe8b.png)