code: protected boolean removeMedia (AbstractMedia media)
      {
          int mpos = _media.indexOf(media);
          if (mpos != -1) {
              _media.remove(mpos);
              media.invalidate();
              media.shutdown();
              // if we're in the middle of ticking, we need to adjust the _tickpos if necessary
              if (mpos <= _tickpos) {
                  _tickpos--;
              }
              return true;
          }
          log.warning("Attempt to remove media that wasn't inserted [media=" + media + "].");
          return false;
      }
docs: Removes the specified media from this manager, return true on success.