Changed definitions so that qsplit is now defined in terms of qfst, qsnd.  AT PRESENT THERE IS NO PATTERN-MATCHING FOR QSPLIT.
Changed definitions so that qsplit is now defined in terms of
qfst, qsnd.  AT PRESENT THERE IS NO PATTERN-MATCHING FOR QSPLIT.

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle