Animations, removing SDL_Image and adding pnglite.

I have two notes about this code at the moment:

* It supports only PNG files (using pnglite). Adding support for libpng and libjpeg is a bit tricky - these libraries use setjmp/longjmp. My proposal is to add a simple wrapper in C to hide error handling from D.

* I replaced Derelict Fontconfig with hand-made Fontconfig interface ("1 to 1" port from C) and I forgot to restore the old version - I needed it to experiment with it and such interface was more convenient.