Mandel Max simple filament holder

During the [building of our second printer](http://www.printingin3d.eu/news/second-printer) we realised we need a simple, but solid filament holder. We wanted something surely won't get stuck. So we created a system to put two bearings and an axis trough the filament roll. And then only a small piece needed to fix it to one of the aluminim profile.
The models were created in [JavaSCAD](https://www.thingiverse.com/thing:83043), our [model generator framework](http://www.printingin3d.eu/javascad