Added support for scaled atlas

I added support for scaled atlas, in the following case:

captura
(https://cloud.githubusercontent.com/assets/7415055/4988478/6bd46f80-6944-11e4-8b51-5b6391d62d6d.png)

I use " Self.animation.SetAtlasScale( 0.12 ) " to tell the scale i used on atlas.