added stub for EventManager
added test sound for a collectible
make EventManager globally accessible
first version of signal slot principle
added Signals to TriggerFields
connect TriggerField with callback functionality
use Slots to listen on contacts of collectible Bodies
open menu Scene via M
added signum function to Jello.Vector2
added Line class
added getDirectedAngle method to Jello.Vector2
added arcTo method to Path
use arcTo method in vector graphics showcase
added insert in order to complete creational methods of Path