Merge pull request #39 from armm77/master

* Fix NPC spawns.
Added some minor events and rewrite Silithus pvp script (just need to add aura remove hook to handle the mound spawns when 29519 is removed by mounting or death).
Wintergrasp: Added some overrides to the destructible objects. (Attempt to avoid them getting deleted during cell unload.) Also some small corrections.
Wintergrasp: Multiple corrections and a bit of cleanup. Also the destructible objects should have override 0x04 as well. (0x04 is not implemented coreside.)
Wintergrasp: Some more cleanup and some experimental things for the upcoming battlefield manager scripting. Now players can see how much time there is until battle even if they are not in Wintergrasp.