Alpha blended font dithering

I added support for solid colorkey truetype font rendering and alpha
blended truetype font dithering to the SDL_ttf package. It’s still
under development (and will probably be used by the Loki Alpha Centauri
port), but you can get a sneak preview at:

This will also be featured in the next Pirates Ho! article. :slight_smile:

See ya!
-Sam Lantinga, Lead Programmer, Loki Entertainment Software