Changes

Use new API for SuperVanish hook to support PremiumVanish as well
Both use the same api, plase just add the latest SuperVanish.jar to your
build path
 https://www.spigotmc.org/resources/supervanish.1331/
https://www.spigotmc.org/resources/premiumvanish-1-8-packet-level-hider.14404/

 Haven't found anything that checks if supervanish is actually loaded,
if there is one please make it check if premiumvanish is enabled as
well, thanks.
 (commit: f78573a)