raycaster speedup - Geometry / BufferGeometry / Indexed-BufferGeometry

Here is the new pull request. 
This version uses the hitbox for all geometry types.
I included the chnages that you suggested in your comments.  

I found a problem in some cases with floating point roundings. 
(http://en.wikipedia.org/wiki/Round-off_error)
I solved it by just expanding the hitbox by 0.0001.

I have the new test cases here:

Geometry:
http://www.gsx.de/threejs_test/raycast/webgl_interactive_draggablecubes.html

BufferGeometry:
http://www.gsx.de/threejs_test/raycast/webgl_interactive_draggablecubes_bufferGeometry.html

Speedtest with Indexed-BufferGeometry:
http://www.gsx.de/threejs_test/raycast/index.php?NormalThreeJS=0&ModelSmall=1&countIterations=100


best regards 
Benedikt