Uninvited guests.

Map updated. Changes:

1. Dexter's specialization has been changed. Now, at the beginning of the battle, he casts Vampirism on creatures of the first three levels.
2. Rupert's specialization has been changed. Now, he specializes in ballista. It receives +1 to attack for each level of the hero. Also, the hero himself receives +1 to attack for every 4 levels.