code: function parseAbbreviation(key, value) {
  		key = utils.trim(key);
  		var m;
  		if ((m = reTag.exec(value))) {
  			return elements.create('element', m[1], m[2], m[4] == '/');
  		} else {
  			// assume it's reference to another abbreviation
  			return elements.create('reference', value);
  		}
  	}
docs: Parses single abbreviation
  @param {String} key Abbreviation name
  @param {String} value Abbreviation value
  @return {Object}