Added instances for ReifiedFold.
Added instances for ReifiedFold.

This permits you to drop into it and use it as an applicative way merge
folds.

Icelandjack/lens,cdepillabout/lens,timjb/lens,danidiaz/lens,rpglover64/lens,Fuuzetsu/lens,omefire/lens,cchalmers/lens,hvr/lens,ddssff/lens,Gabriel439/lens,hvr/lens