Add instances for more types from base

[langston-barrett]

Specifically:

• Data.Functor.Compose.Compose
• Data.Functor.Const.Const
• Data.Functor.Identity.Identity
• Data.Functor.Product.Product
• Data.List.NonEmpty.NonEmpty
• Data.Word.Word
• Data.Word.Word16
• Data.Word.Word32
• Data.Word.Word64
• Numeric.Natural.Natural

I checked the encoding against Aeson's in ghci, not sure if there's a good way to mechanically ensure they line up (i.e., in a test suite).

[thomasjm]

This function derives instances for a bunch of examples, which are then tested against various Aeson Options in the different test files.

I guess you could add some more types here to exercise these instances.

[thomasjm]

I'll go ahead and merge this and see if I can add some tests...