Support shortcut/tunnel edges for minimap tile creator

[biosp4rk]

The minimap tile creator doesn't support shortcut edges. This only affects one tile in sector 3 near the sector 5 shortcut. Tiles with a shortcut edge require special handling:

• Only one of the left/right sides should have a tunnel
• The walls above/below the tunnel should be drawn two pixels in from the edge
• Instead of being centered, tile content should drawn one pixel left/right away from the tunnel
• There should always be a top and bottom wall