Update to 0.16
    
    - New upstream release 0.16
      - Previously, using a default with a positional parameter would result in an
        error when compiling the validator subroutine; defaults now work with
        positional parameters (GH#5)
      - Moose and Specio types (and coercions) that provide variables to close over
        when being inlined did not always compile properly; most notably, this was
        not being handled at all for Moose types, and not completely handled for
        Specio coercions