Synced with mrdoob's skinning branch. Also fixed broken canvas cube example.

That one was bugging me, I thought it was integration when it was a simple misspelling ;)

examples/canvas_geometry_cube.html

@@ -171,7 +171,7 @@
 
 			function render() {
 
-				plane.rotation.z = cube.rotation.y += ( targetRotation - cube.rotation.y ) * 0.05;
+				plane.rotation.y = cube.rotation.y += ( targetRotation - cube.rotation.y ) * 0.05;
 				renderer.render(scene, camera);
 
 			}