Code review comment for lp:~inkscape+alexander/inkscape/offset-cubic-improvement

Hi Alexander, I just fix the problem as I try to tell in IRC. Also comment some cool improvements copied from IRC:

The Fix:
https://inkscape.org/en/paste/10473/
you need to apply to current trun geom-patstroke.cpp

The comments:
Just to know: is posibol remove overlaps when the offset in a path time value <= 0? Or is too complex. I could do with libarot in mayority cases but for example in the same SVG of climb when line join has a hight value, inside line cross outside line-
If this kind of work is done... simplify at ~80% the offset LPE, realy geom-pathstroke can do all work without boolops and without Livarot.

One cuestion about new tolerance.
¿Can it have a default value with similar process time than previous version? a deefault value in half_outline and in outline so you can use this parent and grandparent functions with tolerance
or with default value.