Reduce amount of SQL queries needed to get the content
Reduce amount of SQL queries needed to get the content

First, a UNION query is used to determine whether we do have
any content for the current object and region, then we use that
knowledge to only query the tables with some content inside.

mjl/feincms,feincms/feincms,pjdelport/feincms,nickburlett/feincms,matthiask/django-content-editor,pjdelport/feincms,matthiask/django-content-editor,michaelkuty/feincms,matthiask/django-content-editor,joshuajonah/feincms,pjdelport/feincms,joshuajonah/feincms,matthiask/django-content-editor,mjl/feincms,michaelkuty/feincms,joshuajonah/feincms,feincms/feincms,nickburlett/feincms,joshuajonah/feincms,michaelkuty/feincms,mjl/feincms,nickburlett/feincms,hgrimelid/feincms,hgrimelid/feincms,feincms/feincms,nickburlett/feincms,matthiask/feincms2-content,matthiask/feincms2-content,hgrimelid/feincms,matthiask/feincms2-content,michaelkuty/feincms