Comment 0 for bug 1409568

This patch maps the colours used from a custom inkscape pallet to an 8 pen 1980's style plotter. its does this by mapping colours to a pen. Its modifies a few files including hpgl_enclode.py hpgl_output.pl hpgl_output.ink. More options have been added to the dialogue save box. when saving a hpgl file. The original pen select option is still there but when 0 is selected then multiple pens are used. I have attached a test file also. colour-test.svg that will draw a line with each pen in order from bottom to top.