pgsql: Allow extracting machine-readable object identity

Allow extracting machine-readable object identity

Introduce pg_identify_object(oid,oid,int4), which is similar in spirit
to pg_describe_object but instead produces a row of machine-readable
information to uniquely identify the given object, without resorting to
OIDs or other internal representation.  This is intended to be used in
the event trigger implementation, to report objects being operated on;
but it has usefulness of its own.

Catalog version bumped because of the new function.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/f8348ea32ec8d713cd6e5d5e16f15edef22c4d03

Modified Files
--------------
doc/src/sgml/func.sgml              |   29 +-
src/backend/catalog/dependency.c    |  816 +--------------
src/backend/catalog/objectaddress.c | 2031 ++++++++++++++++++++++++++++++++++-
src/backend/commands/alter.c        |   52 -
src/backend/parser/gram.y           |   63 +-
src/backend/utils/adt/format_type.c |   26 +-
src/backend/utils/adt/regproc.c     |   52 +-
src/include/catalog/catversion.h    |    2 +-
src/include/catalog/dependency.h    |    3 -
src/include/catalog/objectaddress.h |   13 +-
src/include/catalog/pg_proc.h       |    3 +
src/include/utils/builtins.h        |    4 +
12 files changed, 2140 insertions(+), 954 deletions(-)