Signal.add() will now throw an error if the same callback is added twice (feature #1020)
fix typo
use Vector.<Function> instead of Array in Signal to get a ~10% performance boost
fix Signal.add() and Signal.remove() error checks to take the tmp _toAdd/_toRemove tmp lists into account
optimized worldToLocal retrieval in MeshController
fix RenderingController.bind() to avoid listening to the same scene/mesh bindings twice