allow listVersions to return only prereleased versions. generate pom via new DSL gem which handles prereleased gems as SNAPSHOTS
allow the gem artifact to be  for released gems or prereleased gems. the latter will be SNAPSHOT artifacts
IT tests for the prereleased gem artifacts
use the regular maven2GavCaculator is good enough
use released maven-tools
disallow prerelease gems on non-prereleased repos
added tests for prereleased gem artifact repos