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.
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
Fixes cowbell morale boost

Was intended to give a max of 15 + 15 more for every MUTCAT_CATTLE
mutation of the player, up to 150, but due to an error each mut gave 8
times more max morale than it was meant to.
Fix %% typo when reading books
Strip trailing spaces from map screen per issue #6478
Stripped spaces per issue #6478. For real this time.
display message on skill level increase
Merge pull request #6505 from dvolk/msg-on-skill-increase

display message on skill level increase
Emergency fix for leading zero in comestibles.json.
Merge pull request #6508 from Rivet-the-Zombie/leading-zero-fix

Emergency fix for leading zero in comestibles.json.
Merge pull request #6498 from 9600bauds/cowbell

Fixes cowbell morale boost
Make armor item category translatable
Merge pull request #6513 from BevapDin/translate-item-category

Make armor item category translatable
Merge style, warning, and translation cleanups.
Merge https://github.com/CleverRaven/Cataclysm-DDA