Refactored fields to support any # of fields.

The field class is now a wrapper that contains a vector of any number of
fields at once. So now you can choke on smoke, burn in fire, and melt in
acid all at the same time. Fields now propagate additively... so if
something is spewing smoke instead of overwriting the old smoke, it adds
to its density.
Studious Nature Trait

Changes Fast Reader to Studious Nature, gain morale from learning from
books (Independant of books' fun rating), and also gain some focus fro
reading.  Also reduced focus loss from reading without trait, as it
meant reading a skill book for 10 minutes made you incapable of learning
ANYTHING for like 2 days which sucks.
Fixed some weird spreading behavior with smoke and fire.

Smoke now lasts longer and generates faster indoors, but small fires are
much less likely to destroy a building (density 1 fires). Fire will last
a more reasonable length of time.
Studious Nature Take 2

Rebalanced values, split studious nature from fast reader.
Spelling Fix

Oops, retyped fast reader trait wrong. Fix'd
Yet Another Value Tweak

Morale boost back to 4, cap raised to 20. Should mean longer study
sessions generate more morale (There's nothing a scholarly type likes
likes better than curling up in a warm snuggie in front of a fire in his
post-apocalyptic fortress with his favorite copy of Mechanical Mastery)
Comments and monster field changes

If a field spawns ontop of you you will now be hit by it immediately.
Also commented things.
Studious Nature Take 3 (Errors)

Implementing Funnyman's suggestions on coding,  getting errors in
game.cpp about "not declared in this scope".  Have to leave for
vacation, but if anyone could look at this and tell me what's wrong I'll
try to fix tonight if hotel has WiFi.  Sorry this is kind of sloppy, I
have ZERO coding experience and I'm just sorta flailing around here :)

PS  Thanks for all the help Funnyman you're awesome.  This would have
gone nowhere without your comments!
Fixes NPC Morale Penalty
Take 4

OK at hotel with notebook running.  Fixed pldata.h error by switching (
to { (hooray this keyboard actually has that ... uh spiky parentheses
thing I still don't know the name of)  After looking at some of the
other code put a u. in front of has_trait and add_morale which seemed to
clear up the errors codeblocks was giving me; now if I only knew what u.
meant I might have some confidence I'd actually fixed it.  Posting this
so everyone can see and tell me what massive coding screwup I've made
THIS time.  But hey, that's how we learn :)
Merge multi-field per tile support.

Conflicts:
	field.cpp
	game.cpp
	inventory.cpp
	mapdata.h
	npc.cpp
Merge new character invlet assignment fix, magic number removal, and a start at gettext support.
Code Cleanup

Trying my hand at proper code etiquette. I think I got it all straight,
but I'm not certain.  It looks good in notepad++ at least.
Added gettext -l flags for Windows builds.
Merge pull request #1834 from FunnyMan3595/win_load_gettext

Added gettext -l flags for Windows builds.
Merge PR #1815

Conflicts:
	player.cpp