Forage Balancing

(u.skillLevel("survival") + ((u.per_cur / 2 - 4) + 3))
CommentUpdate

Due to new herbs, which shares spawns
Foraging overhaul

Results of foraging are now defined in these item groups:
forage_spring
forage_summer
forage_autumn
forage_winter

Initial values in these groups should be similar of what was defined in
nested if hell.
Changes are now easier to do and testing can be done in Test Item Group.
Merge branch 'SeasonalForageBallance' of https://github.com/Robik81/Cataclysm-DDA into forage
Merge branch 'ForageOverhaul' of https://github.com/Robik81/Cataclysm-DDA into forage

Conflicts:
	src/game.cpp

Compromise: Survival gives a bigger boost, and Peception is leveled a bit.