Smarty type testing for params and returns

For example:

``` js
/**
 * Shouldn't report
 * @param {String} a
 * @returns {String}
 */
function (a) {
  if (a.indexOf('x')) {
    return '?';
  }
  return a + 'b';
}

/**
 * But this should report
 * @param {Number} b
 * @returns {String}
 */
function (b) {
  return b.quantity / 2;
}
```
