code: function _getReverseMap() {
      if (!this._REVERSE_MAP) {
        this._REVERSE_MAP = {};
        for (var key in _MAP) {
  
          // pull out the numeric keypad from here cause keypress should
          // be able to detect the keys from the character
          if (key > 95 && key < 112) {
            continue;
          }
  
          if (_MAP.hasOwnProperty(key)) {
            this._REVERSE_MAP[_MAP[key]] = key;
          }
        }
      }
      return this._REVERSE_MAP;
    }
docs: reverses the map lookup so that we can look for specific keys
  to see what can and can't use keypress
  
  @return {Object}