Default exception handler
          Instances of ExceptionalEvent can have a default handler block that is run if the exception occurs outside of a when:do expression. 
          | anException |
          (anException := ExAll newChild)
             defaultHandler: [:signal |
               self error: 'The exception was not expected at this time.'].
          anException signal.
          If desired, the default handler block can be run from inside of a handler block by sending handlesByDefault to the handler's signal argument. 
          Note:
          The exitWith: and retry messages cannot be used in the default handler block unless the expression that caused the exception was run inside the receiver block of a when:do: expression. 
         
        
          Last modified date: 01/29/2015