Fixed Auto flags and added polygonal regions in claim command. Also removed sources from jar

[Qveshn]

Details:

1. Added version substitute from build.gradle to plugin.yml
2. Remove sources (java) from jar
3. clean task now also cleans target dir
4. Use fake actor to add auto flags to region in claim command (Issue: #22)
5. Added the ability to claim polygonal regions who have permission "worldguard.region.unlimited" (as WorldGuard does)