Crash fixes (fixed #2, fixed #3)

[afrixs]

I investigated the code a bit and found reasons of some reported issues, fixed the problems and tested on all provided polygons.
Problematic was (in most cases) duplication of a point when connecting a hole to the outer polygon. The duplicated point wasn't handled properly afterwards.
Example

             Hole
          ---------
          |       |
          |  A B  |
          ---+ +---
  Connection | | 
             | |           C
-------------+ +----------+-------
                   Outer polygon

A and B are a duplicated point (they have the same coordinates)
Cut line was sometimes mistakenly drawn from C to A (should be C to B) or from A to B.

Also fixed a mistakenly written line in acd2d_data.cpp in foundBoundary which caused errors.

Also added coloring of final polygons and a display option of showing point coordinates for a better visualisation and further potential debugging