updated homepage for "sdl-mixer"
added virtual package "conf-sdl2-mixer" for the C lib SDL_mixer 2.0
updated homepage for "sdl-image"
added virtual package "conf-sdl2-image" for the C lib SDL_image 2.0
added virtual package "conf-sdl2-net" for the C lib SDL_net 2.0
added virtual package "conf-sdl2-ttf" for the C lib SDL_ttf 2.0
fixed pkg-config for sdl2-net
fixed pkg-config for sdl2-image
new homepage for "sdl-ttf" 1.2
added ubuntu's "depext" for virtual package "conf-sdl-mixer"
homepage for "sdl2"
added ubuntu's "depext" for virtual package "conf-sdl-gfx"
added ubuntu's "depext" for virtual package "conf-sdl-image"
added ubuntu's "depext" for virtual package "conf-sdl-ttf"
added "depexts" for debian and ubuntu for virtual package "conf-sdl2-ttf"
added "depexts" for debian and ubuntu for virtual package "conf-sdl2-net"
added "depexts" for debian and ubuntu for virtual package "conf-sdl2-image"
added depexts for "debian" and "ubuntu" for virtual package "conf-sdl2-mixer"
Merge pull request #1681 from fccm/master

conf-sdl-mixer & conf-sdl2-mixer