python - be: Move the TIF_Repr into htup_repr.

Log Message:
-----------
Move the TIF_Repr into htup_repr. The tif repr routine is no longer necessary
as obj_repr will just use ts->typoutput(recordout), and it is unlikely for a
need to externalize again. (Although, if that is not the case it will likely
appear in heaptuple.c, instead of tif)
Remove unused contains function for now.
Various touch-ups.

Modified Files:
--------------
be/src:
tif.c (r1.3 -> r1.4)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/tif.c.diff?r1=1.3&r2=1.4)
heaptuple.c (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/heaptuple.c.diff?r1=1.2&r2=1.3)
be/include/pypg:
tif.h (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/include/pypg/tif.h.diff?r1=1.2&r2=1.3)