pgsql: Make SQL arrays support null elements.

Log Message:
-----------
Make SQL arrays support null elements. This commit fixes the core array
functionality, but I still need to make another pass looking at places
that incidentally use arrays (such as ACL manipulation) to make sure they
are null-safe. Contrib needs work too.
I have not changed the behaviors that are still under discussion about
array comparison and what to do with lower bounds.

Modified Files:
--------------
pgsql/contrib/intagg:
int_aggregate.c (r1.21 -> r1.22)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intagg/int_aggregate.c.diff?r1=1.21&r2=1.22)
pgsql/contrib/intarray:
_int_tool.c (r1.4 -> r1.5)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/_int_tool.c.diff?r1=1.4&r2=1.5)
pgsql/contrib/tsearch2:
query_rewrite.c (r1.2 -> r1.3)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/query_rewrite.c.diff?r1=1.2&r2=1.3)
pgsql/doc/src/sgml:
array.sgml (r1.46 -> r1.47)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/array.sgml.diff?r1=1.46&r2=1.47)
config.sgml (r1.36 -> r1.37)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml.diff?r1=1.36&r2=1.37)
func.sgml (r1.292 -> r1.293)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.292&r2=1.293)
xfunc.sgml (r1.107 -> r1.108)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xfunc.sgml.diff?r1=1.107&r2=1.108)
pgsql/doc/src/sgml/ref:
insert.sgml (r1.29 -> r1.30)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/insert.sgml.diff?r1=1.29&r2=1.30)
pgsql/src/backend/catalog:
pg_proc.c (r1.135 -> r1.136)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/pg_proc.c.diff?r1=1.135&r2=1.136)
pgsql/src/backend/executor:
execQual.c (r1.183 -> r1.184)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execQual.c.diff?r1=1.183&r2=1.184)
pgsql/src/backend/optimizer/util:
clauses.c (r1.201 -> r1.202)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/util/clauses.c.diff?r1=1.201&r2=1.202)
pgsql/src/backend/utils/adt:
acl.c (r1.127 -> r1.128)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/acl.c.diff?r1=1.127&r2=1.128)
array_userfuncs.c (r1.16 -> r1.17)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/array_userfuncs.c.diff?r1=1.16&r2=1.17)
arrayfuncs.c (r1.123 -> r1.124)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/arrayfuncs.c.diff?r1=1.123&r2=1.124)
arrayutils.c (r1.18 -> r1.19)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/arrayutils.c.diff?r1=1.18&r2=1.19)
float.c (r1.115 -> r1.116)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/float.c.diff?r1=1.115&r2=1.116)
int.c (r1.68 -> r1.69)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/int.c.diff?r1=1.68&r2=1.69)
numeric.c (r1.86 -> r1.87)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/numeric.c.diff?r1=1.86&r2=1.87)
oid.c (r1.64 -> r1.65)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/oid.c.diff?r1=1.64&r2=1.65)
ruleutils.c (r1.207 -> r1.208)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c.diff?r1=1.207&r2=1.208)
timestamp.c (r1.157 -> r1.158)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/timestamp.c.diff?r1=1.157&r2=1.158)
pgsql/src/backend/utils/cache:
lsyscache.c (r1.129 -> r1.130)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/cache/lsyscache.c.diff?r1=1.129&r2=1.130)
pgsql/src/backend/utils/fmgr:
funcapi.c (r1.26 -> r1.27)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/fmgr/funcapi.c.diff?r1=1.26&r2=1.27)
pgsql/src/backend/utils/misc:
guc.c (r1.299 -> r1.300)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c.diff?r1=1.299&r2=1.300)
postgresql.conf.sample (r1.170 -> r1.171)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/postgresql.conf.sample.diff?r1=1.170&r2=1.171)
pgsql/src/include:
c.h (r1.190 -> r1.191)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/c.h.diff?r1=1.190&r2=1.191)
pgsql/src/include/catalog:
catversion.h (r1.306 -> r1.307)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.306&r2=1.307)
pg_proc.h (r1.388 -> r1.389)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h.diff?r1=1.388&r2=1.389)
pgsql/src/include/utils:
acl.h (r1.86 -> r1.87)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/acl.h.diff?r1=1.86&r2=1.87)
array.h (r1.55 -> r1.56)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/array.h.diff?r1=1.55&r2=1.56)
pgsql/src/pl/plpgsql/src:
pl_comp.c (r1.94 -> r1.95)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_comp.c.diff?r1=1.94&r2=1.95)
pl_exec.c (r1.154 -> r1.155)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_exec.c.diff?r1=1.154&r2=1.155)
pgsql/src/test/regress/expected:
arrays.out (r1.26 -> r1.27)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/arrays.out.diff?r1=1.26&r2=1.27)
domain.out (r1.34 -> r1.35)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/domain.out.diff?r1=1.34&r2=1.35)
pgsql/src/test/regress/sql:
arrays.sql (r1.21 -> r1.22)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/arrays.sql.diff?r1=1.21&r2=1.22)