- Changed the processing_complete flag to event_wait, reversing it's
  behaviour in the process. Commands must now trigger the waiting for
  an event to finish the processing of a command. When doing so, these
  command processes must signal the ACCOUNT object when the event being
  waited for happens so that further commands may be accepted.
- Renamed event_wait to wait_for_event in MENU_ITEM so that it matched
  the functions used to get/set it.
- The command cmd_reset can be used to reset the command system when it
  gets into a messy situation. Ideally this command will not be
  permanent.