Prevent a divide-by-zero bug in SHAPE_ARC::ConvertToPolyline.
When the radius is zero, just use the initial angle (it makes
no different anyway, the result is the centre point, which is
the start point.
(cherry picked from commit e312e2b286)
Corrects an error in polyline estimation
Syncs graphics to world PNS by whole layer set rather than
individual layer at a time.
Prevents reloading of full pns TOOL_BASE during reset of tools unless
the tool is being activated.
Fixes: lp:1766626
* https://bugs.launchpad.net/kicad/+bug/1766626