Move Functor[S] constraint on Free out of structure, onto functions.
Move Functor[S] constraint on Cofree out of structure, onto functions.
Fix Free examples.
indSeqInstance
IndSeqArbitrary
IndSeq instances test
Merge pull request #619 from S11001001/topic/constraints-out-of-free-cofree

Move Functor evidence out of Free/Cofree data, ask for it on operations instead