Yet another Poly Snaps

For quite some time i was inspired by archimedic and solids and I created them in the past. But when I lately found out, that Mathgrrl has snaps without axles, my fascination was revived. However her idea did not fully match my requirements, So i added few features:

* All the Hinges have sphere caps now , so the hinges auto-align
* The hignes can bend from -120 to 120 degrees, which allows to create small tetraeders up to very concave polyeders
* the hinge exactly sits at the virtual pos