V3.0.9.1 RC

Tweaks

1. New option in config.yml to turn off invites for coops. (general -> coopisrequest: true)
2. Block values can now be negative values (fixed)
3. API - added IslandPreDeleteEvent

Bug Fixes

1. [Major] Issue with island leader losing island due to old team members joining server with old data in their player file.
2. [Major] API - fix NPE when getting island that does not exist
3. [Medium] Team members were not getting teleported back to island if they fell into the void when invincible visitors was active.
4. [Medium] Invincible visitor settings - Players were not treated as "visitors" if they were outside their protected island area, but within the island range.