Frame, dialog and config file couldn't agree on whether to use
internal units or not.
Frame now stores internal units, and they're now mapped on the
way in/out of the config file. Dialog was already assuming they
were stored in internal units (though they were previuosly not).
Fixes: lp:1751435
* https://bugs.launchpad.net/kicad/+bug/1751435
Also adds indicators in layers palette for feedback.
Also generates sized images for all indicators instead of using
scaled bitmaps (which didn't look great).
Also fixes a completely unrelated typo in a UI string.
Jeff Young
Michael
jean-pierre charras