Merge pull request #265 from Morphan1/master

Added <player.list>, <player.list.online>, and <player.list.offline> tags.
Greatly simplify WorldScriptHelper code.
Hide chat trigger stacktraces so as to not needlessly panic the populace.
Add "on player changes hunger" world event. Allow setting of new targets in "on entity targets entity" by using: - determine target:<entity>
Add "on entity spawns" and "on lightning strikes" world events.
Add "on entity explodes" world event. Order groups alphabetically in WorldScriptHelper.
Add "on block burns", "on entity tamed" and "on player tames entity" world events.
Fix nasty 'negative logic' error with IF.
Merge branch 'master' of https://github.com/aufdemrand/Denizen
Fix dPlayer being cast to LivingEntity in Feed command.
Add "on player clicks in inventory" and "on player changes gamemode" world events.
Clean up debugging messages.
Merge branch 'master' of https://github.com/aufdemrand/Denizen
Catch NPEs in CustomNBT methods.
Prevent error from inventory click world event.
Add <player.equipment> tags back in.
Add <context.item> to "on player right clicks item_frame" world event.
Added 'on player changes sign', removed random debug