Stage performance quick fix

Currently, all non blocking bricks need at least one entire frame for execution. So it seems, that the stage is slow and unable to put up with complex animations. But in fact, computation time is wasted.

The quick fix solves these problems by using a small delta for the actions to update. Instead refreshing the actions one time with "delta", the actions are refreshed "n" times with "delta / n".

A short movie, which demonstrates the performance difference:
https://dl.dropbox.com/u/42800985/ActionsPerformance.mp4