Implement the functions from Maplike in terms of KeysValuesAll

[danidiaz]

In this library, Maplike is used for functions like pure_Record that do not require constraints from the map values. KeysValuesAll is used for functions like cpure_Record that do require constraints.

In sop-core, the analogue of Maplike is SListI, and type SListI = All Top.

So perhaps we should Implement Maplike in terms of KeysValuesAll, which is the analogue of All in this library.