Parametric GT2 belt clip with square teeth

A customizer-friendly remix of [jcdoll's GT2 belt clip](http://www.thingiverse.com/thing:117987), with square teeth.
Unfortunately, the original clip didn't work for me - my printer wasn't able to reproduce the teeth well, and the belt kept on slipping (for the real-world difference see the 4th image). While very subtle, this change made it work for me.
This remix includes both the original jcdoll's thing and my remix. In the customizer, you can turn on both and see the difference, and maybe