pgsql: Document get_call_result_type() and friends; mark

Log Message:
-----------
Document get_call_result_type() and friends; mark TypeGetTupleDesc()
and RelationNameGetTupleDesc() as deprecated; remove uses of the
latter in the contrib library. Along the way, clean up crosstab()
code and documentation a little.

Modified Files:
--------------
pgsql/contrib/dblink:
dblink.c (r1.42 -> r1.43)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/dblink/dblink.c.diff?r1=1.42&r2=1.43)
pgsql/contrib/pgstattuple:
pgstattuple.c (r1.18 -> r1.19)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgstattuple/pgstattuple.c.diff?r1=1.18&r2=1.19)
pgsql/contrib/tablefunc:
README.tablefunc (r1.11 -> r1.12)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tablefunc/README.tablefunc.diff?r1=1.11&r2=1.12)
tablefunc.c (r1.35 -> r1.36)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tablefunc/tablefunc.c.diff?r1=1.35&r2=1.36)
tablefunc.sql.in (r1.9 -> r1.10)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tablefunc/tablefunc.sql.in.diff?r1=1.9&r2=1.10)
pgsql/contrib/tablefunc/expected:
tablefunc.out (r1.11 -> r1.12)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tablefunc/expected/tablefunc.out.diff?r1=1.11&r2=1.12)
pgsql/contrib/tablefunc/sql:
tablefunc.sql (r1.10 -> r1.11)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tablefunc/sql/tablefunc.sql.diff?r1=1.10&r2=1.11)
pgsql/contrib/tsearch2:
ts_stat.c (r1.10 -> r1.11)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/ts_stat.c.diff?r1=1.10&r2=1.11)
wparser.c (r1.8 -> r1.9)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/wparser.c.diff?r1=1.8&r2=1.9)
pgsql/doc/src/sgml:
xfunc.sgml (r1.102 -> r1.103)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xfunc.sgml.diff?r1=1.102&r2=1.103)
pgsql/src/backend/utils/fmgr:
funcapi.c (r1.22 -> r1.23)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/fmgr/funcapi.c.diff?r1=1.22&r2=1.23)
pgsql/src/include:
funcapi.h (r1.17 -> r1.18)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/funcapi.h.diff?r1=1.17&r2=1.18)