Replace AIMaster m_lEventQueue with a priority queue

[Liareth]

This is a big optimization if your module has a lot of queued events (many areas, many delaycommands, lots of fighting, lots of effects, etc). Previously events that were not immediate would be added to the linked list in AddEventAbsoluteTimeViaTail which would iterate backwards over every calendar entry until it found a place to insert.

Side effect: Events with the same time of day are now executed in an undefined order. E.g:

DelayCommand(0.0f, First());
DelayCommand(0.0f, Second());

Who knows which one will happen first? I certainly don't. But if you don't care about that, and your server is big and full of events, this could be a valuable optimization for you.

[Daztek]

Just a bunch of minor things, also don't forget to update CHANGELOG.md!