Potential overload rework

[ssk97]

Casting a spell with Overload converts all "target" text to "each". Currently this is done by having entirely separate effects. Instead, we can apply the effects after setting up a FixedTargets.

I have not yet finished converting all Overload cards, once I do I will remove the old OverloadAbility constructor. Currently only A-D cards have been modified. Several of the more complex Overload cards will require merging the target and overload effect implementations as the target version uses getFirstTarget.

I was wondering if this seemed worth finishing. I don't expect it to fix any bugs, just remove a lot of repetitive code.

[xenohedron]

I endorse this direction

(just make sure there's adequate test coverage)