v1.5.4 - Fixed Nicknames and TShockIRC comp.

By changing order to 6, this will now handle the chat after TShockIRC
(With an Order of 5), which in theory should pass nicknamed users into
the channel.

My theory would be that since they had the same order, TShockIRC was handling after Essentials supposing TShock uses alphabetic order with plugins (didn't check, but should due to C# standards).