1) Make sure that layer dependencies don't prevent us from drawing
drill marks.
2) Don't draw pad shapes when their particular layer isn't enabled
(a side effect from the above)
3) Allow the printout painter to set a different hole colour (the
special case for through-hole pads was handled twice anyway -- once
in LoadColors() and once in draw( D_PAD ).
4) Replace the call to getDrillSize() which handles swapping in the
small mark size if set.
Fixes https://gitlab.com/kicad/code/kicad/issues/4847
Remove extraneous use of FLAG0 from tracks cleaner (it was checked but
never set).
Fix issue in expand connections where two parts of it couldn't agree
on the same flag (BUSY vs SKIP_STRUCT), and where the second part was
clearing the flag instead of setting it.
Remove obsolete HIGHLIGHT infrastructure (we now use selection).
Remove extraneous use of BUSY flag in several places (it was never
set).
Note: this is a basic implementation but it could be
improved once we include bus information in the netlist
and pcbnew can natively keep track of buses and nets
instead of just nets.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/4158
Jeff Young
jean-pierre charras
Marek Roszko
Jon Evans