- PNS_ITEMSET now keeps ownership info (does not rely on PNS_ITEM::Owner(), avoiding the risk of dangling pointers)
- fixed vias losing connected traces when dragging in mark obstacles mode
- fixed rare segfault when board item returned null netclass
- re-worked PNS_LINE_PLACER and PNS_ROUTER classes a bit, removing duplicate class members
- cleaned up Andrew's blind/buried via fixes
- fixed 'custom via width' dialog bug updating the width even when closed/cancelled
- fixed incorrect radius of drawn microvias
2) PNS router incorrectly detects collisions with blind/buried vias that don't actually intersect the active layer
3) PNS router silently converts blind/buried vias to through-board vias when shoved