Refactored OBJLoader and OBJMTLLoader.
* OBJLoader now parses line per line in the same way OBJMTLLoader does.
* No more reusing of the same vertices array.
* Both now create a Object3D when finding a "o" and a Mesh when finding a "g" (or "usemtl").
* I used to like the obj format.
TrackballControls: Implemented pinch gesture for zooming. Thanks @ericnoble.
Sadly I didn't get the damping to work...
Fixed typo in canvas_camera_orthographic2. Fixes #2849.