python - lo: Reorganize the project and incorporate the 'ex' module.

Log Message:
-----------
Reorganize the project and incorporate the 'ex' module.

It's formal name is now 'pg_foundation' in light of its evolution from a
namespace definition package into a more general purpose module-set.

Details:
 - Declare namespace packages for setuptools
 - Relocate postgresql.backend.typoid to postgresql.types and provide
   additional information about standard Postgres types.
 - Move all the exception classes and data into postgresql.exceptions
 - Removed postgresql.encodings as its integration with Python's encoding
   was far from elegant. This is further complicated by setuptools which
   doesn't guarantee that all __init__.py files in a namespace package will
   be executed. Thus making the auto-import of postgresql.encodings impossible
   to guarantee upon the importation of the 'postgresql' module.

Modified Files:
--------------
    lo:
        README (r1.1 -> r1.2)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/README.diff?r1=1.1&r2=1.2)
        setup.py (r1.17 -> r1.18)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/setup.py.diff?r1=1.17&r2=1.18)
    lo/postgresql:
        __init__.py (r1.5 -> r1.6)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/__init__.py.diff?r1=1.5&r2=1.6)
    lo/postgresql/backend:
        __init__.py (r1.3 -> r1.4)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/backend/__init__.py.diff?r1=1.3&r2=1.4)
    lo/postgresql/protocol:
        __init__.py (r1.1 -> r1.2)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/protocol/__init__.py.diff?r1=1.1&r2=1.2)
    lo/postgresql/utility:
        __init__.py (r1.2 -> r1.3)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/utility/__init__.py.diff?r1=1.2&r2=1.3)
    lo/postgresql/utility/client:
        __init__.py (r1.2 -> r1.3)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/utility/client/__init__.py.diff?r1=1.2&r2=1.3)

Added Files:
-----------
    lo/postgresql:
        exceptions.py (r1.1)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/exceptions.py?rev=1.1&content-type=text/x-cvsweb-markup)
        types.py (r1.1)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/types.py?rev=1.1&content-type=text/x-cvsweb-markup)

Removed Files:
-------------
    lo/postgresql/backend:
        typoid.py
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/backend/typoid.py)
    lo/postgresql/backend/interface:
        __init__.py
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/backend/interface/__init__.py)
    lo/postgresql/encodings:
        __init__.py
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/encodings/__init__.py)
        bytea.py
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/encodings/bytea.py)
    lo/postgresql/interface:
        __init__.py
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/interface/__init__.py)
    lo/postgresql/meta:
        __init__.py
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/meta/__init__.py)
    lo/postgresql/meta/interface:
        __init__.py
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/lo/postgresql/meta/interface/__init__.py)