code: @Override
      public boolean add(BugInstance bugInstance) {
          return add(bugInstance,
                  bugInstance.getFirstVersion() == 0L && bugInstance.getLastVersion() == 0L);
      }
docs: Add a BugInstance to this BugCollection. This just calls add(bugInstance,
  true).
  
  @param bugInstance
  the BugInstance
  @return true if the BugInstance was added, or false if a matching
  BugInstance was already in the BugCollection