Fixes extreme slowness of Geometry.rayIntersection.

You are all going to love this pull request!

It fixes an extreme inefficiency in 'Geometry.rayIntersection' caused by using the 'indices' property rather than the '_indices' member. This was making three copies of the entire index array for EVERY triangle.

Ray intersections with complex models is now actually usable.

Enjoy!

Chris.
Merge pull request #72 from ChrisDenham/patch-9

Fixes extreme slowness of Geometry.rayIntersection.