TODO:
-----

 -- Document current API.
 -- Fix file headers.
 -- Run splint all over it, and fix errors.
 -- Generalize copy-pasted DB handling code
 -- Support GEOIP_COUNTRY_EDITION_V6 somehow (separate db type?)
 -- consider removing db type constants from binding
 -- Support regions.
 -- Bind whole API.
 -- Capture not only stderr, but stdin as well,
    libgeoip spams there as well.
 -- Write better tests.
 -- Open by DB type leaks 18KB+ (that's how libgeoip written).
 -- Add a luajit.ffi binding
