One major fix to SMN/SCH: give Bane a cooldown/mp cost, and stop making it consume AF stacks.

The nerf to its damage spread means it's not OP anymore (especially on a SCH), and there's no longer a way to spread DoTs when in Trance, and with our new extra finicky system of AF stacks in place, it really doesn't make sense. Fester and Painflare feel like they have the oomph needed to use up AF; Bane just does not, and since we have no AoE filler and a super long cooldown on Shadowflare, giving Bane a small cooldown (10 sec? 15?) instead of being an AF consumer would do a lot.