Investigate HUD to show possible conflicts when holding a cross-layer item

[Daedeross]

When a player has in their hand and item that build on two layers (subterra-belt-elevator-*, subterra-telepad-*, or subterra-power-*) show within a moderate radius (~20 tiles?) where there are conflicting entities on the bellow of above layer. If the player is holding a 'down' item, it will show entities on the layer below, if holding an up entity it will show conflicts on the layer above.

• [x] Research LuaRendering
• [x] Implement drawing of bounding boxes.
• [x] Benchmark and test refresh rates.
• [x] Add per-player setting to toggle it.
• [x] Implement HUD for when holding a power-column.

[Daedeross]

Seems plausible, needs some more testing for performance. This is what my first whack at it looks like:

[Daedeross]

This seems to be working well, however with the change to power-transfer, this will need a bit more work for that.