#111 more FDT/FlashBuilder warnings removed

`Input` class got two new classes: `KeyData` and `KeyState`. They will eliminate the silly look ups (and those warnings). This will affect `Keyboard` and `FrameRecord` class.

`FlxSprite` got a safe cast of `_animation[i].name as FlxAnim`. `_animation` array only holds `FlxAnim`.

I can solve the most others as well by safe casting. Not sure if it is worth.