Squashed commit of the following:

commit 690c540e541333cee3155b81f0e5756876e6d37b
Author: Martin Saturka <martin.saturka@sourcefabric.org>
Date:   Wed Mar 27 15:24:08 2013 +0100

    LB-368: Chained blogs - plugin
    adjusting

commit 4ce1b34839254db8e4eaf2a00e2a6f1282f26ea5
Author: Martin Saturka <martin.saturka@sourcefabric.org>
Date:   Wed Mar 27 14:27:24 2013 +0100

    LB-368: Chained blogs - plugin
    * model implemented