Add script for Tortured Druids/Sentinel in Silithus

* They will now emote and spawn a Hive'Ashi Drone on death (75% chance).
* Tortured druid also had its combat AI added.
All spell IDs are correct.
Timers and threshold for tortured druid are guesswork (probably close to
correct) based on
similar NPCs scripts.

Thanks Metalica for his contribution. Closes #9

Related to Classic DB issue:
https://github.com/classicdb/database/issues/653
Merge pull request #11 from cala/hive_ashi_drones

Add script for Tortured Druids/Sentinel in Silithus