source changed to actually create the Entities only when needed else put the creation time in a list for the future

Conveyer checks if canAccept each time a moveEnd. Conveyer also moves entities from haveToDispose if a callerObject is given

new appendEntity added to CoreObject for use inside removeEntity. Appends entity to an object internal queue. To be overridden by Assembly object where entities are appended to Frame internal queue

CoreObject updated to facilitate the signalling of the Router if the receiver to be preempted is operated