python - ctl: Use pg_config dictionary.

Log Message:
-----------
Use pg_config dictionary.

Refactor get_parameters into get_parameters and select_parameters.
Correct __repr__ implementations.
Bump version.

Modified Files:
--------------
    ctl:
        setup.py (r1.5 -> r1.6)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/ctl/setup.py.diff?r1=1.5&r2=1.6)
    ctl/src:
        cluster.py (r1.3 -> r1.4)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/ctl/src/cluster.py.diff?r1=1.3&r2=1.4)
        control.py (r1.2 -> r1.3)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/ctl/src/control.py.diff?r1=1.2&r2=1.3)
        init.py (r1.3 -> r1.4)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/ctl/src/init.py.diff?r1=1.3&r2=1.4)