Split lighting conditions out to torch/los/perma-lit/dark, so that tiles
and ascii can represent lit rooms/line-of-sight/torchlight correctly.

Lit rooms in ascii that are out of los are now pale blue floors - but
this can be overridden in the feature knowledge/visuals settings.

Note: all floor colours in src/cave.c:461-464 are now fully configurable
in visuals/prefs - these colours should probably be moved across to the
pref files instead of being set here.
8x8 tile rubble and discoloured spot traps previously had wrong tile
definitions for bright/dark - fixing now.
Make ascii tile lighting mimic existing lighting settings. It's still
fully configurable, but the changes should be pretty much unnoticable
when playing in ascii.
Update message parser to use symbols and add entry for MSG_BOLD. [1798]
Fix ainu message.
Add PowerWyrm's fix for kill sound for uniques. [1799]
Remove button module. [1770]
Remove mouse_buttons option.
Treat key as a string. [1800]
Clean up some player_can functions and add generic player parameter.
Clean up player resting functions.
Remove redundant floor check. [1790]
Update graphics flavor files.
Fix a few things with flavored artifacts. [1646]
Replace monster list code with monster list module. [1611]
Make subwindow list stuff more efficient for flicker animation.
Fix sorting and adjust main term bounds.
Fix padding for multibyte strings.
Add object list module.
Add sound names to z-msg-list and fix some things in sound.cfg. [1748]