pgsql: Add error location info to ResTarget parse nodes.

Log Message:
-----------
Add error location info to ResTarget parse nodes. Allows error cursor to be supplied
for various mistakes involving INSERT and UPDATE target columns.

Modified Files:
--------------
pgsql/src/backend/commands:
analyze.c (r1.92 -> r1.93)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/analyze.c.diff?r1=1.92&r2=1.93)
copy.c (r1.260 -> r1.261)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/copy.c.diff?r1=1.260&r2=1.261)
pgsql/src/backend/nodes:
copyfuncs.c (r1.331 -> r1.332)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/copyfuncs.c.diff?r1=1.331&r2=1.332)
equalfuncs.c (r1.267 -> r1.268)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/equalfuncs.c.diff?r1=1.267&r2=1.268)
outfuncs.c (r1.271 -> r1.272)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/outfuncs.c.diff?r1=1.271&r2=1.272)
pgsql/src/backend/parser:
analyze.c (r1.331 -> r1.332)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/analyze.c.diff?r1=1.331&r2=1.332)
gram.y (r2.536 -> r2.537)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y.diff?r1=2.536&r2=2.537)
parse_relation.c (r1.121 -> r1.122)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_relation.c.diff?r1=1.121&r2=1.122)
parse_target.c (r1.141 -> r1.142)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_target.c.diff?r1=1.141&r2=1.142)
pgsql/src/backend/utils/adt:
not_in.c (r1.44 -> r1.45)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/not_in.c.diff?r1=1.44&r2=1.45)
pgsql/src/include/nodes:
parsenodes.h (r1.305 -> r1.306)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/parsenodes.h.diff?r1=1.305&r2=1.306)
pgsql/src/include/parser:
parse_target.h (r1.38 -> r1.39)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/parser/parse_target.h.diff?r1=1.38&r2=1.39)
pgsql/src/test/regress/expected:
alter_table.out (r1.93 -> r1.94)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/alter_table.out.diff?r1=1.93&r2=1.94)