Also fixes some plot bugs with arcs.
Also moves polygonization of arcs (when required) in plotting code
from 5 degrees to calculated based on ARC_HIGH_DEF.
Fixes https://gitlab.com/kicad/code/kicad/issues/5017
ADDED arc, circle and rectangle shapes for schematic. Shapes support
line styles and fill colors.
CHANGED sheet background color in Edit Text & Graphics Properties to
fill color (and it now affects shapes).
Pushed STROKE_PARAMS down into common and moved all shapes to using it
for stroke descriptions.
Jeff Young
Marek Roszko