Made mutation categories actually matter.

The primary mutation category now has significant influence. Traits from
other categories have a high chance of being removed. It is now very
difficult to end up with every single trait in the entire game.
Mutagens that cause mutation only in specific categories.

There are still a lot missing.
Added the remaining specific mutagens.

For now they use very general recipies.
Add brass catcher item, functionality, craft recipe, and spawn locations.
Replace some of the melee weapons in gun nut basement with gun extras.
Merge PR #1492 - stop crashing with human flesh, couple other things
Merge PR #1486 - CBM crafting/disassembly
Merge PR #1491 - brass catcher (collects spent ammo shells)

Conflicts:
	mapitemsdef.cpp
Merge remote-tracking branch 'upstream/master'
Make movement take half the cost of both the beginning and end tiles,
in stead of just taking the cost of the end tile.
Also use combined_movecost() for NPC moves, and path length calculation.
Move monster movecost calculation to its own function for consistency.
Use calc_movecost() for path length estimation.
Fix silly mistake.
Merge MK II power armor.
Merge pull request #1495 from yobbobanana/movecost_update

Oops.
Merge remote-tracking branch 'dda/master' into dda-master
Merge enhancements to mutation system.
Merge remote-tracking branch 'upstream/master'