pgsql: Add the possibility to specify an explicit validator function for

Log Message:
-----------
Add the possibility to specify an explicit validator function for foreign-data
wrappers (similar to procedural languages).  This way we don't need to retain
the nearly empty libraries, and we are more free in how to implement the
wrapper API in the future.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        catalogs.sgml (r2.197 -> r2.198)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/catalogs.sgml?r1=2.197&r2=2.198)
        keywords.sgml (r2.22 -> r2.23)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/keywords.sgml?r1=2.22&r2=2.23)
    pgsql/doc/src/sgml/ref:
        alter_foreign_data_wrapper.sgml (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_foreign_data_wrapper.sgml?r1=1.1&r2=1.2)
        create_foreign_data_wrapper.sgml (r1.1 -> r1.2)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_foreign_data_wrapper.sgml?r1=1.1&r2=1.2)
    pgsql/src:
        Makefile (r1.44 -> r1.45)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/Makefile?r1=1.44&r2=1.45)
    pgsql/src/backend/catalog:
        information_schema.sql (r1.52 -> r1.53)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/information_schema.sql?r1=1.52&r2=1.53)
    pgsql/src/backend/commands:
        foreigncmds.c (r1.5 -> r1.6)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/foreigncmds.c?r1=1.5&r2=1.6)
    pgsql/src/backend/foreign:
        Makefile (r1.1 -> r1.2)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/foreign/Makefile?r1=1.1&r2=1.2)
        foreign.c (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/foreign/foreign.c?r1=1.2&r2=1.3)
    pgsql/src/backend/nodes:
        copyfuncs.c (r1.423 -> r1.424)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/copyfuncs.c?r1=1.423&r2=1.424)
        equalfuncs.c (r1.347 -> r1.348)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/equalfuncs.c?r1=1.347&r2=1.348)
    pgsql/src/backend/parser:
        gram.y (r2.658 -> r2.659)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y?r1=2.658&r2=2.659)
        keywords.c (r1.209 -> r1.210)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/keywords.c?r1=1.209&r2=1.210)
    pgsql/src/bin/pg_dump:
        pg_dump.c (r1.524 -> r1.525)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dump.c?r1=1.524&r2=1.525)
        pg_dump.h (r1.152 -> r1.153)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dump.h?r1=1.152&r2=1.153)
    pgsql/src/bin/psql:
        describe.c (r1.200 -> r1.201)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/describe.c?r1=1.200&r2=1.201)
        tab-complete.c (r1.179 -> r1.180)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/tab-complete.c?r1=1.179&r2=1.180)
    pgsql/src/include/catalog:
        catversion.h (r1.523 -> r1.524)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h?r1=1.523&r2=1.524)
        pg_foreign_data_wrapper.h (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_foreign_data_wrapper.h?r1=1.2&r2=1.3)
        pg_proc.h (r1.536 -> r1.537)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h?r1=1.536&r2=1.537)
    pgsql/src/include/foreign:
        foreign.h (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/foreign/foreign.h?r1=1.2&r2=1.3)
    pgsql/src/include/nodes:
        parsenodes.h (r1.391 -> r1.392)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/parsenodes.h?r1=1.391&r2=1.392)
    pgsql/src/test/regress/expected:
        foreign_data.out (r1.6 -> r1.7)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/foreign_data.out?r1=1.6&r2=1.7)
    pgsql/src/test/regress/sql:
        foreign_data.sql (r1.4 -> r1.5)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/foreign_data.sql?r1=1.4&r2=1.5)

Removed Files:
-------------
    pgsql/src/backend/foreign/dummy:
        Makefile
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/foreign/dummy/Makefile)
        dummy_fdw.c
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/foreign/dummy/dummy_fdw.c)
    pgsql/src/backend/foreign/postgresql:
        Makefile
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/foreign/postgresql/Makefile)
        postgresql_fdw.c
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/foreign/postgresql/postgresql_fdw.c)