Show place menu when right clicking

* Move method to mousePressed and test for event.isPopUpTrigger instead
  of right mouse click
* Add view back into Handlers constructor
* Implement delete method to controller
* Ensure delete method removes from petrinet
Explain what EscapableDialog is
Added place editor menu

* PlaceEditorPanel now shows options to edit name, tokens and capacity
* Added capcity logic into Place
* PetriNetComponent interface has name and id methods
Move show popuo to PlaceTransitionObjectHandler mousePressed method
wrap creating arc in mousepressed into an if
Transition Popup

* Everything except for set rate is implemented
Add arc popup menu
Remove jeval from project

* Add maven dependency
 Modify change structure

* Implement Transition, Place and Arc controllers
* Move PetriNetController methods into relevant controller
* Add tests for new controllers
* PetriNetComponents now are observable, PetriNet observes changes in them
* Add AbstractPetriNetComponent abstract class that wraps obervable
* Remove PetriNet from HistoryItem since no longer need a call to petriNet.update()
Remove uncessesary code in PlaceHandler

* Delete TestingPlaceHandler, its no longer used