Updated pathing to support time interval input during the update callback of level.m.
Issues: The project builds fine but I'm getting this error below:

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2013-05-01 13:21:06.478 pull[7735:303] *** Assertion failure in -[CCLayer addChild:], /Users/nathan/Documents/code/Pull/src/pull/libs/cocos2d/CCNode.m:382
2013-05-01 13:21:06.478 pull[7735:303] Argument must be non-nil
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I get a blank white screen when I run the project.
Refactored Level to LevelLayer.
Merge branch 'pathing'