made changes to vertex for V-Slot Extrusion.

The vertex needed a few tweaks for the V-Slot Extrusion.
*using T-Nuts had to move the holes a little so the Tnuts would fit.
*Added Makefile so i dont have to compile in openscad.
*Increased the Fin size so that it fits into the vslot better.
*warnings about the missing scad files, i re-added them from the
original kossel commit
*Removed Stl Files (can be generated with makefile)