5.0.0 - GriefPrevention integration

Hey,

After countless reports about issues with my island protection implementation with last versions, I've decided to completely replace the old island protection and trusting system with GriefPrevention plugin integration. This way things are a lot more clean on the development side and the island protection is free of loopholes and bugs. The plugin can still be used without GriefPrevention, but all the protection features will be disabled.

How does it work?

To enable island protection, GriefPrevention plugin must be installed on the server. After updating islands, the plugin tries to create claims to all existing islands with their respective owners. These claims are admin claims and the island owners have build and managment rights. This results players being unable to delete these claims by hand and also makes sure that players don't need claimblocks to create and protect islands. The islands plugin also handles the deletion and transferring of these claims for players.

Players should still be able to use /trust or /containertrust on their island to trust their friends. Islands plugin shouldn't also interfere with any other claims than the island claims in islands world. By default the plugin overwrites GriefPrevention world mode settings for islands and wilderness worlds.

Cheers!

Edit: Due to some technical issues with how Spigot works, GriefPrevention is required on all servers for now. It can still be disabled though. I also added a version that doesn't require it, in case there's someone who absolutely doesn't want to touch gp.