parseElement = function (element) {
    if (!element) return null;
    if (element.required && (element.type !== 'boolean')) {
      return element;
    }

    var prop = _.find(element.properties, function (property) {
      return parseElement(property);
    });
    if (prop) {
      return prop;
    }

    if (element.items) {
      if (_.isArray(element.items)) {
        prop = _.find(element.items, function (item) {
          return parseElement(item);
        });
      }
      else {
        prop = parseElement(element.items);
      }
      if (prop) {
        return prop;
      }
    }
  }
Returns true if the form displays a "required" field.

To keep things simple, the function parses the form's schema and returns
true as soon as it finds a "required" flag even though, in theory, that
schema key may not appear in the final form.

Note that a "required" constraint on a boolean type is always enforced,
the code skips such definitions.

@function
@return {boolean} True when the form has some required field,
 false otherwise.