Simple 2D-scanner

This thing came from an exercise/question given by a friend of mine:

Can we generate some glasses frame which fit for existing eyeglass lenses without much effort? For example for third world countries?

Result is the following:
1. print the simple 2D scanner with a size which is appropriate for you. Either make the slots big enough for a folding yardstick or condierably smaller to use a sliding caliper. Also the number of "measurement points" may be changed
2. When you have printed it out, put a screw throug the top thread in order to fix the part you want to scan
3. Measure for each slot what the caliper or yardstick is telling you and put the data in the second file. This will render a simple surface with the scanned shape for you.

As an example I have made some eye glasses, but I didn't put too much effort in making them really useable. It is a proof-of-concept.

TODO:
- code could be possibly simplified
- maybe add routines to make real eye glass frames
- add splin