craftyjs/Crafty — pull request #601 by mucaho (2013-11-03 06:50:05+00:00)
Title: Extension of Gravity component - moving platforms

In a platformer you sometimes have moving platforms.
If you do not attach the player to the platform, he just falls off it when the platform moves away.
Therefor I added an optional argument ```shouldAttach``` to the ```gravity``` constructor.

Example usage can be seen in the qunit tests.