Go for it!
The only real thing that I am asking you to do is if you distribute the
source code for PureMVC,
in its original or a modified form, then you must leave in the attribution that you see in each class:
/*
PureMVC - Copyright(c) 2006, 2007 FutureScale, Inc., Some rights reserved.
Your reuse is governed by the Creative Commons Attribution 3.0 United States License
*/
You may add your own statements, but that's it; nothing more to be concerned about.
If you're making a commercial application based on the framework and the source code itself is not part of the package, (which is most likely the case), then you need not include any attribution at all.
This is an open-source framework. The fact that there aren't a bunch of people working on it and that the development phase of the project is over with no future expansion plans doesn't matter. It's open source, do with it what you will.
-=Cliff>