Fixed prototype bug with CheckMedia related to the queryList

Added event ON_CHANGE to the QueryList
Added parameter to Page.find with new parent function call (parent is always an element).
Added error messages if a node does not exist.
Added referencing this.element._nodeData which self references back to the actual Class. This allows only one node object to be constructed instead of a new one every time Find was called (Node have tested this for potential memory leeks but so far JS seems to still garbage collect the object even though there is a double self reference, will have to test on all browsers though).
Added Node.getWidth which returns a px value int of the element width;
Added Node.getHeight which returns a px value int of the element height;
Added Node.find method that finds a node within its element using the new parent parameter described above.
Added Node.P which is just a shortcut to Node.find.
Added object.getNumObservers to AVObj.attachObserverModel method.