Fixes volume of gasoline.
Updates trait struct to handle mutations

*whistles*
Add power_mutation

Probably the biggest method to work with
Change my_traits and my_mutations to vectors

Cause now they'll be assigned keys, so order is important.
Filled in more missing methods

Yay.
Makes 'chop down tree' action check for TREE flag instead of t_tree terrain.
Keybinding Stuff

My most recent attempt to get the action useable in game. Still working
on it though.
More Keybinding Stuff

Still not working >.<
FOUND IT!

Found the tiny missing line or registering actions that I needed to add
my mutations menu too! IT SHOWS UP!
Fixes some minor issues

Functioning Screen Now!
Fixes more issues

Whee.
Get activated mutations to do things

added debug active mutation
Drains hunger/thirst/stamina instead of power

YAY
Moves mutagen to its own separate inventory category.

It doesn't really seem like it fits with 'drugs'. Also this category
contains purifier as well, since it's intrinsically linked with mutagen.
Merge branch 'gasoline-volume-fix' of https://github.com/Rivet-the-Zombie/Cataclysm-DDA into merge2
Merge branch 'tree-fix' of https://github.com/Rivet-the-Zombie/Cataclysm-DDA into merge2
Fix name collision

PR didn't sync completely, apparently.
Adds firefighter and police starting scenarios.

What's so special about these as opposed to starting in the evac shelter
as a firefighter or cop? If you choose one of these you start in a fire
or police station full of zombies, but the cost of your choice of
profession is reduced via an intrinsic property of the scenario system
so there's a bit of incentive points-wise to start in a
less-advantageous environment specific to that profession for a more
appropriate (and difficult) origin scenario.

tl;dr - Get cheaper professions in exchange for a more Fun start.
Acorn-y fixes.

Hooray for missing entries!
Reduces charcoal kiln light radius.

Seriously, this thing is brighter than a lantern.