Add ooze-shield and fix the len bug in the ascii stl reader.
Update main file to split up processing function into a class. Added wipe-tower support.
Ignore internal holes on bridge detection.
Catch exceptions if they happen in Clipper and abort.
Update to version 13.11.2
Comb and retract on support printing.
Enable ooze-shield code for support material with 2nd extruder.
Only add the skirt/brim for the first extruder.