[Plugin: Multiple Post Thumbnails] Commerical Use?

Hi, I was wondering if it would be ok for me to include this plugin as part of my theme? I do plan on selling the theme on themeforest so wanted to see if it was ok.

Thanks.

http://wordpress.org/extend/plugins/multiple-post-thumbnails/