Pie tiles
Don't prompt about sacrifices with auto_sacrifice set to false

When the option is disabled, players should be left to make their own
decisions about what to do with items. Keep the current behaviour
(prompts to ignore items) when auto_sacrifice is set to "prompt_ignore".
Allow monsters to displace submerged monsters.

This avoids having monsters stuck behind a hidden trapdoor spider: now
they can swap spaces with the spider, even if they don't "outrank" it.
We still do the normal habitibility checks, so this won't push a fish
out of water or anything like that.
Note suppression and sentinel's mark in the logfile
Fix a problem with namespace collision

The old version barely used the hyper namespace but there was a slight collision with the new version.
Omnigrid subdivider
Layered grid layout

Utilising some very basic hyper features to draw up to three grids on top of each other
Properly fix namespace clash
Cave town layout (incomplete but looking nice)
Tweaked cave city
 Fix radial procedural
Cocytus ice berg layout
Add a box procedural
Another cave layout variant
Another cave layout

I think there are enough cave layouts now.
Simplify and comment the aggregate procedurals
Slightly tweak a cave layout

Using existing procedurals as negative space to create holes in the architecture
Wheels layout (Zot, Snake)
Procedural CSG

Complex layout shapes can be prototyped and rendered very quickly using these building blocks and modifiers.
A new layout using the procedural CSG functions

It makes all kinds of interesting geometrical halls.