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);
						}
					}
Parses single abbreviation
@param {String} key Abbreviation name
@param {String} value Abbreviation value
@return {Object}