Add feature WebSocket

Restore ommited comments
Change test mode to INSTANCE_MODE_SINGLE
Code Review of WebSocket feature

Change notes:
  Removed obviously unused/faulty code
  Renamed/Clarified connection names
  Recovered async-Event handling.

Review notes:
  Change introduces a ComponentUpdate.isProcessed()
     feature. I still have no clue how this relates
     to the WebSocket feature in general.
  Also change introduce the case handling for components
     without a peer at all. Not sure how this case is
     relevant, because all components are required to have
     an peer?
  ApplicationInstance handles concurrent disposal
     This case should not be possible at all.
  Component introduces a lastRenderId
     Same here: Mysterious use case.
Resolve Jetty dependencies