fixed several bugs reported on forum:
- necromancy issues
- fix for lookout tower
- Sir Mullich is unavailable
- first hero is awakened on next turn
- give 500 XP on defeating hero

git-svn-id: http://svn.code.sf.net/p/vcmi/code/trunk/@3459 4dfc6b2a-8b31-0410-aa91-d6c70e3ac834