#86 Add MakeStem to String Class / MakeString to Stem Class

[mdlueck]

To paralle the high performance I/O made available
between Array and String classes, make the same
possible except to Stem objects.

Need to add:
MakeStem to String Class
MakeString to Stem Class

Current use of Array / String objects look like the
following snips:

/ This code requires at least ORexx 2.1.3 on Win32 /
file~LineOut(FINDarray~MakeString())

/ This code requires at least ORexx 2.1.1 on Win32 -
only tested with >=2.1.2 /
INstr=file~charin(1, FILEsize)
FINDarray=INstr~makearray()