python - be: Squish some bugs.

Log Message:
-----------
Squish some bugs.

One nasty bug that forgot to increment the EmptyPyPgTupleDesc.(Could have been
causing weird failures.)
One that decref'd an object to zero prior to use. =\
Refactor PyPgHeapTuple and PyPgTupleDesc to use the new pattern: PyPgX_NEW.
[More transitions coming later w.r.t. PyPgX_NEW instead of PyPgX_Initialize]

Modified Files:
--------------
    be/include/pypg:
        cis.h (r1.11 -> r1.12)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/include/pypg/cis.h.diff?r1=1.11&r2=1.12)
        heaptuple.h (r1.9 -> r1.10)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/include/pypg/heaptuple.h.diff?r1=1.9&r2=1.10)
        query.h (r1.10 -> r1.11)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/include/pypg/query.h.diff?r1=1.10&r2=1.11)
        tupledesc.h (r1.9 -> r1.10)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/include/pypg/tupledesc.h.diff?r1=1.9&r2=1.10)
    be/src:
        function.c (r1.21 -> r1.22)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/function.c.diff?r1=1.21&r2=1.22)
        heaptuple.c (r1.15 -> r1.16)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/heaptuple.c.diff?r1=1.15&r2=1.16)
        module.c (r1.27 -> r1.28)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/module.c.diff?r1=1.27&r2=1.28)
        query.c (r1.20 -> r1.21)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/query.c.diff?r1=1.20&r2=1.21)
        tupledesc.c (r1.14 -> r1.15)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/tupledesc.c.diff?r1=1.14&r2=1.15)