[Performance Increase] Replace prototype forEach/map within ui-grid for better performance

http://jsben.ch/N3AVA

Looking at the performance of the faster ForEach/map functions written you can see that significant performance increase happens over the built in forEach/map prototype on a javascript array.

I saw that ui-grid uses the built in prototypes and figured they could use a performance increase so that ui-grid becomes more responsive with larger grid sizes. The larger the array, the more significant of a performance increase it has!