function Dispatch () {
    this._nodes = {}; // a container for constant time lookup of nodes

    this._queue = []; // The queue is used for two purposes
                      // 1. It is used to list indicies in the
                      //    Nodes path which are then used to lookup
                      //    a node in the scene graph.
                      // 2. It is used to assist dispatching
                      //    such that it is possible to do a breadth first
                      //    traversal of the scene graph.
}
The Dispatch class is used to propogate events down the
scene graph.

@class Dispatch
@param {Scene} context The context on which it operates
@constructor