3-dimensional Z-level support, Core Part 5: ranged sight and attacks. [$110]

[GlyphGryph]

Master Ticket #6822
This will be a "bounty issue" for the development of z-line track development.

This issue concerns interaction between z-levels

This has following requirements:
Enemies with ranged weapons should be able to fire on the player from other z-levels
The player should be able to press a key to view a lower or higher z-level
The player should be able to view details on other z-levels
The player should be able to fire on other z-levels

There is a $110 open bounty on this issue. Add to the bounty at Bountysource.