Fix NPE when player teleports, Fix factions tag being displayed in disabled worlds and added a custom event

I found few bugs while I was testing the plugin to install in my server. My server runs mcpc-plus with protocollib and factions, when a faction event occurred the tags were not updated because the plugin didn't use the new faction state, an other bug was that when a player teleport and the destiny has a player nearby an NullPointerException would be thrown because Bukkit.getPlayer(name) would return null even with the player online, so when that happened I scheduled an update in the next ticket. An other bug was that I disabled factions in some worlds and also disabled it in the BattleTags config file but it would still show the factions tag because it was not checking if factions was disabled in that world.

And as an extra I added a custom event to allow other plugins to manipulate the resulting tag, I did that because I also use ColoredTags plugin in my server, it's different because it uses scoreboard instead of changing the name of the entity, I use it to show if a player has special tags. It was being incompatible with this plugin because BattleTags changed the entity name so it wouldn't match the name in the team, then I created a plugin to add the colored entity name to the team and it's now working perfectly. I didn't include the plugin in your source, just the event needed to my plugin work.

I tested the changes extensively and didn't find any issue, everything is working perfectly now in my server.

Ah, the revert was because I typo, I tried to undo the commit but I failed and created a revert, then I just recommit with the typo fixed