customizer angle

Dear all,

this part is still under construction. The customizer needs more care from my side.
And I do need to add the option how fine (hex-bolt) the resolution of the screws shall be.


Features of this part:

- distances of screws from left/right and top/bottom can be modified
- campher can be done inside/outside/none
- number of screws adjustable
- thickness adjustable
- a "extra-strong" version can be printed. Number of triangles can be defined

as said, part is still under construction.

todo
====
by now it is easy to trick yourself and I need to add some sanity-checks.
For example if you set "screw_distance_border_left_right" to e.g. 20, then it means that the part must be at least 40mm width. But if you set the width smaller, then the screw-holes are messed up. I am working on this.

thanks

christian