Update to May GeoIP database
Please review my branch geoip-may2013 and merge it into maint-0.2.2 and subsequent maintained branches.
Also, please merge my branch geoip-manual-update-may2013 into master. MaxMind changed a couple 'A1' ranges that the automatic substitution algorithm couldn't fix and that I had to fix manually. I also tweaked the cleanup script to catch more cases when our manual substitutions need an update.