Archive files

The recent discussion about using archive files led me to create a simple
wrapper for the zip08x library -> SDL_rwops format. zip08x is a
zipfile-reading library available from http://www.ajk.tele.fi/~too/sw/

An explanation and example code for loading SDL_Image data from a zipfile are
at http://campbellhome.dhs.org/~matt/software/zip08x.html

Any comments/bugfixes/etc are appreciated.

-Matt