SMN pet redundancy

[Terk177]

It would be nice to have a way to swap pets on a cooldown (like our own version of swiftcast which uses aetherflow for a quick swap), but again it needs to have a cost (like aetherflow) or a cooldown (or both).

I like the idea of having more uses for Aetherflow other than just Fester. Sure, you can use it for Bane on the occasions you need to spread your dots, or Energy Drain if you're mana starved and the CD on Aetherflow isn't close. But my only issue would be that if you add more uses for Aetherflow, we would need to be compensated with 1-2 more stacks of it.