Add sdl2 extra libraries

[humbertodias]

Would be possible to add SDL2_ttf, SDL2_image, SDL2_mixer, SDL2_gfx?

I saw in another resemble project http://github.com/pspdev/psp-packages that they have already done it

Thanks

[humbertodias]

Added here #64
Using the repository SDL2_PSL1GHT_Libs

• SDL2_PSL1GHT
  • sdl2 - 2.30.0
  • sdl2_image - 2.8.2
  • sdl2_mixer - 2.8.0
  • sdl2_ttf - 2.22.0
  • sdl2_nex - 2.2.0
  • sdl_gfx - 2.0.27

[bucanero]

I see you created a big PR with many changes, but I think it would be better to have a new smaller PR with only these SDL2 libraries so we can review and add them.