AI spell casting priorities

[thejeff]

Targeting is a different issue.

Lowering priorities for Summons, especially gem using summons would be nice. Slow summons while the enemy is already retreating are pointless.

I'd say the AI over prioritizes summons in general. Raise Dead spam is nice, but usually summons aren't that effective.

No gem use when the enemy army is routed? I can't think of a reason. As long as beserk or other unroutable units are considered.