Change teardrop generation to rely more heavily on BOARD_CONNECTIVITY
for improved performance.
Add updating of teardrops on BOARD_COMMIT::Push().
Also converts m_CopperItemRTreeCache to std::shared_ptr.
We don't copy it around anyway, and having to create a new set
of std::unique_ptr's for each operation is likely to be more
expensive than std::shared_ptr's overhead.
This makes it clearer that the overrides are not inverses of each
other -- one overrides the flashing state and the other overrides
the connection state (to other zones, not to everything).
Also fixes a bug where we were failing to check the force-no-connect
for pads.
If the pad hasn't already been owned by another zone, and the zone we're
currently filling can connect to it, then we want to try to flash it even
if it's not connected to anything else.
Fixes https://gitlab.com/kicad/code/kicad/issues/13415
Also adds some debugging to try to catch dangling pointers.
Also adds a cache for group bounding boxes (which will be expensive
to calculate for large groups).
Fixes https://gitlab.com/kicad/code/kicad/issues/12875
1) The highest priority zone that a via/pad collides with "owns" its
connectivity state. Once set, lower priority zones cannot change it --
and in fact, if they would have connected to it are forced not to.
2) The connectivity state goes with the zone fill state, and therefore
must be saved in the file.
3) Display of remove-unconnected's pads is no longer done in GetViewLOD()
(which isn't called for selected items), and is instead done in PCB_PAINTER.
This allows us to draw the full pad in outline mode when a via/pad is
selected which would otherwise only show the hole.
4) Note that in some cases this will still generate DRC errors -- in
particular when a via nearly collides with a higher priority zone it
won't get "owned" by that zone and may therefore have insufficient
clearance if said zone concludes it's unconnected and a subsequent
(lower priority) zone connects to it (causing it to now become flashed).
Fixes https://gitlab.com/kicad/code/kicad/issues/11299