"slider.tpl.php" outside of theme directory

Issue Summary

First, let me start by giving my thanks for such versitile module! :]

I noticed the module loads all html information from "slider.tpl.php". I think this is great, but I would love to see if one could create a "slider.tpl.php" within the active theme directory and would pick it up automatically as an override, making it easy for updates and maintenance. :]

I am not sure it is already possible by adding an override of some sort for the "slider_theme" function, and if so, would love to see it in the module's README file :}
Thanks again for such amazing module.