Based on Add_Guides_In_Range.py (which uses percentages in offset, not in pixels) by Tin Tran, changes made by: MareroQ (also removed dependency on script-fu guides-new.scm).
-add limit px to x/y END,
-added "Draw Guides Pencil" (by active brush, FG color, on new layer) option,
-added "Delete all guides" option.