ACT-895 and oothers

* Modified correction to remove internal Graphiti API reference when
creating a transactional domain.
  
* Consolidated constants into a class ActivitiConstants.java in the 
  utils project and let various other files now point to it rather than
  directly specifying things like extensions or texts.
  
* Modified Properties for asynchronous support. They used the wrong 
  event type FocusEvent of input fields. Rewrote them to use check 
  boxes for their boolean representation and used a SelectionListener
  instead so modifications only occur, when a selection/deselection
  occurrs.
  
* Implemented Call Activity Property selection. This will allow to open
  the appropriate process model when it's ID is found in one of the open
  projects in the Eclipse project explorer. In case multiple processes
  are found, the user is asked to select the one to open. 
  
* Created new package dialog in the utils package to host a modified
  version of the ResourceSelectionDialog, cause this one does not 
  support setting an initial pattern. This refers to bug 36029 in 
  Eclipse, where the appropriate method was available in Eclipse 3.3
  but is no longer existing in Eclipse 4.2.