Use qconvex input file format. Revert commit 7f95e8.

In the commit 7f95e8 the input file format read by sch_creator has been changed.
This commit had break all the conversion script based on blender.

This pull request attend to use the qconvex input file as input file for sch_creator (as instor in commit 61d14).
Also remove the vrml2qconvexinput.py script that is deprecated since qconvex and sch_creator have the same input now.