v0.9.51

More of fixed-format RPG behaves as it does on IBM i, and two bugs found
by the October IBM Ideas portal review are fixed. Each change was checked
against a real IBM i (PUB400).

- I-spec record identification codes now take the zone (Z) and digit (D)
  parts of a position, not only the whole character (C). As on IBM i, '&'
  also matches zone C and '-' also matches zone D. A record belongs only
  to the first record type it matches; rpgc used to let a later type
  claim it too.
- *ENTRY PARM with factor 2 copies factor 2 into the parameter when the
  program returns, as IBM i does. rpgc used to refuse factor 2 there.
- LIKE(ds.field) defines a field like a qualified data structure
  subfield. It used to produce an integer field. A LIKE field now starts
  blank and takes INZ and an initial value.
- OVERLOAD now works when its candidates are prototypes declared
  elsewhere in the source (DCL-PR), not only procedures.

OpenRPG extensions IBM i does not accept: LIKE through a nested data
structure (ds.sub.field), and OVERLOAD telling an IND argument from a
character one.