LBE – minimal balance changes for Heroes V 3.1.

Spells:
- "Raise Dead" now costs 11 mana (instead of 9);
- "Regeneration" now costs 16 mana (instead of 8) and has guild level 3 (instead of 2).

I support this decision - I made something similar for myself a long time ago, but like this:
- Raise Dead to level 3 and cost 11
- Regen to level 3 and cost 11
PS: I don't know if my solution is correct, but all my spells have a cost that depends on their level (i.e., 5, 7, 11, 16, 24 mana units, respectively, with the guild level).