A slight fix for SDL2 for windows compiling.

You shouldn't have to put SDL2 in the root include directory. If your
machine is setup like that, then your machine is setup wrong.
Limits skill gain rate and max level through foraging
Intelligence determinates maximum level of survival level attained during foraging
Add foragable bird and reptile eggs, injects them to recipes
Created egg material, herbivore code modified to acount for new material
Other comestibles accounted for material change
Trash items
Foraging for mushrooms
Lowers egg nutrition values a bit
Adjusts number of items foraged
Spawns foraged items underneath the player
Tweak spawn point
Decreases egg cost for some recipes
fix sign warnings in mutation.cpp
fix sing warnings in live_view.cpp
fix sign warning in overmapbuffer.cpp and player_activites.cpp
fix sign warning in input.cpp and inventory_ui.cpp
fix some sign warnings in game.cpp and astyle
Re-secures Lab and Bunker doors

Hadn't realized that the metal doors were only used with card readers.
This removes my expanding them.  :-/
Changes to vending machine prices