message: fix: Use guard for document.attachEvent calls
  This fixes the issue when Raven is used in NativeScript codebases
diff: @@ -1387,7 +1387,7 @@ Raven.prototype = {
  if (_document.addEventListener) {
  _document.addEventListener('click', self._breadcrumbEventHandler('click'), false);
  _document.addEventListener('keypress', self._keypressEventHandler(), false);
  - } else {
  + } else if(_document.attachEvent){
  // IE8 Compatibility
  _document.attachEvent('onclick', self._breadcrumbEventHandler('click'));
  _document.attachEvent('onkeypress', self._keypressEventHandler());
  