Add \Xmf\Module\Helper::getClass($name, bool $required = false) method

[zyspec]

Enhancement
If would be useful to have the ability to use \Xmf\Module\Helper to load a class file that doesn't have a handler (like interfaces, misc minor classes, etc). The code would be similar to the loadLanguage() and getHandler() methods but all it does is checks to see if the class is loaded (e.g. exists), or if not check to see if file exists and then does either an include_once or require_once. The method then logs the results and returns true|false.

Invoking the class would then just be \Xmf\Module\Helper->getClass('constants', true); to load the Constants interface (in this example).