createElement shortcut
@param  {String} tag
@return {Element} element
function el(element) {
  var classes = [];
  var tag = element;
  var el;

  if (isElement(element)) {
    return element;
  }

  classes = element.split('.');
  if (classes.length > 1) {
    tag = classes[0];
  }
  el = document.createElement(tag);
  addClass(el, classes.slice(1));

  return el;
}