use the CGAL triangulation with intersections enabled. attempt to fix issue #159
print only a single warning about intersecting vertices at dxf tessellation
, instead of spamming it over and over. also mention that it might be
due to intersecting lines, not just duplicate vertices (duplicate vertices
being perhaps generated by cgal's tessellator when it deals with intersecting
lines)
fix print statement
Capitalize 'duplicate'
new test results (degenerate polygons produce output)
Merge branch 'master' of github.com:openscad/openscad into issue159
make it clear to the user that they can't rely on this behavior
Merge pull request #255 from openscad/issue159

Issue159