Add clearfix in sorting slidedown

This makes all sorting groups appear horizontally aligned.
Add userbadge support based proposal sorting (votedetail)

This adds proposal support by each votedetail enabled userbadge to Solr
and allows to sort by support of these user groups.

Note that this only adds score (pro minus con) and not most votes, most
ayes, most nays, controversy for the user badges, as this wouldn't
easily fit within the current UI.