Allow to specify OR-filters in SolrPager
Allow to specify OR-filters in SolrPager

This allows to specify an additional filters with multiple alternatives
(logical OR).

The extra_filter and alternatives_filter parameters only allow for
certain and not arbitrary logical combinations: those which are
currently required in Adhocracy.

liqd/adhocracy,liqd/adhocracy,alkadis/vcv,phihag/adhocracy,phihag/adhocracy,liqd/adhocracy,DanielNeugebauer/adhocracy,phihag/adhocracy,phihag/adhocracy,alkadis/vcv,DanielNeugebauer/adhocracy,phihag/adhocracy,DanielNeugebauer/adhocracy,alkadis/vcv,liqd/adhocracy,DanielNeugebauer/adhocracy,alkadis/vcv,DanielNeugebauer/adhocracy,alkadis/vcv