Merge pull request #217 from takkaria/cave-refactor

Pull CunningGabe's v4 fixes to use more predicates and flags instead of direct feature checks
Port ewert's LOS trap changes to V.

Conflicts:
	lib/edit/p_class.txt
	lib/edit/p_race.txt
	src/cmd1.c
	src/files.c
Add a passive chance to detect mimics.
Fix running.
Start separating traps from other terrain.

Conflicts:
	src/types.h
Remove assertion.
Separate trap bases from traps, and other misc fixes.

Conflicts:
	src/types.h
Fix trap detection, and remove pick_trap().

Conflicts:
	src/cave.c
Add trap.txt to lib/edit/Makefile, fixing make_install.

Conflicts:
	lib/edit/Makefile
Remove traps from terrain.txt, and remove mention of FEAT_INVIS.

Conflicts:
	src/cave.c
Start new searching system, and remove chest traps.

Conflicts:
	src/cmd1.c
	src/cmd2.c
	src/externs.h
	src/game-cmd.c
	src/object/obj-desc.c
	src/spells2.c
Misc trap cleanup.

Conflicts:
	src/cave.c
Add some traps, and enforce min/max levels for trap creation.
Save and load traps properly.
Fix trap allocation bug.

Conflicts:
	src/types.h
Trap code cleanup.
Modify chance to find mimics, and add passive lurker detection.

Conflicts:
	src/cmd1.c
Fix trap deletion and trap saving.

Conflicts:
	src/cave.c

Conflicts:
	src/cave.c
Fix running bug with traps.
Prevent items from ending up on known trap squares.