Merge pull request #1159 from gnif/develop

[multiworld] Adds seed argument and creation usage help.
Merge pull request #1160 from gnif/develop

Adds verbose multiworld help and CSV support to permission group parsing.
Fixed multiworld command permissions.
Fixed serious bug in multiworld which can crash worlds.
Fixed derp.
Yet another derp. I feel ashamed.
[permissions] fixed reversed logic for events.

EventBus.post returns true if the event was cancelled.