add pom.xml
update README
remove markdown formatting from README
update pom to support Sonatype's "Central Sync Requirements"

include license, url and developer info per:
https://docs.sonatype.org/display/Repository/Sonatype+OSS+Maven+Repository+Usage+Guide?#SonatypeOSSMavenRepositoryUsageGuide-6.CentralSyncRequirement
Update geoip-api version in pom.xml
Remove buildr's buildfile, it seems more complicated than using maven for most people.