component : update config with joint to cartesian position

this configuration for the lineardelta uses a component that
translates the joint positions to the cartesian positions. Since
the JA4 branch is not merged yet this is a temporary solution in
getting the correct nozzle velocity for use with velocity
controlled extrusion.

install:
comp --install lineardeltajointscartesian.comp

This component is directly taken from the lineardelta kinematics.
script : update scripts for better parsing the slic3r gcode file

sometimes the slic3r retract/unretract is not consistent.
correct-retract-on-next-layer.py corrects that

added also author.py and g1tog23.py (from linuxcnc website) to
have all the prerequisits for running the cleanup script in
one location

furthermore I have fixed the removing of some temporary files
which had been commented out for debugging purposes
scripts : fix small issue of wrongly commented printline
Merge pull request #213 from luminize/vel-control-extruding

velocity controlled extruding update