Merge branch 'public_next' into master

.gitattributes

.gitignore

.travis.yml

appveyor.yml

comptime.sh

libs/.gitattributes

libs/SDL2/BUGS.txt

libs/SDL2/COPYING.txt

libs/SDL2/CREDITS.txt

libs/SDL2/INSTALL.txt

libs/SDL2/Makefile

libs/SDL2/README-SDL.txt

libs/SDL2/README.txt

libs/SDL2/WhatsNew.txt

libs/SDL2/docs/README-android.md

libs/SDL2/docs/README-cmake.md

libs/SDL2/docs/README-directfb.md

libs/SDL2/docs/README-dynapi.md

libs/SDL2/docs/README-emscripten.md

libs/SDL2/docs/README-gesture.md