Remove Alternative instance about concurrify HOT 4 CLOSED

If structure is monad then it could potentially be Monad{Plus,Or,Zero} with sequential semantics and Alternative in that case would be derived from corresponding instance, in which case one might want to have different alternative instance for concurrent version. (same argument for Fluture#89 if then want to make it Monad* then the alternative instance you proposed might not be valid.)

from concurrify.

Not going to move forward with this idea for now.

from concurrify.

I'm going to remove the hard requirement for Alternative instance from Concurrify. A user will only need to pass in concurrent ap. I'm doing this because I need it for another project I'm working on.

from concurrify.

On closer inspection, I'm going to leave this library as-is, and create something else after all.

from concurrify.