Fix search queries containing spaces.

This should fix a problem introduced in e382665ced489c216b3f05cce538e17a0c59f2e8: Searches containing spaces do not work anymore, searching for "Some Band" lead to searches for "Some%Band". The search term gets encoded in SearchCtrl, but not decoded again in SearchResultsCtrl.

Also the artist name coming from the route does not get decoded correctly in ArtistCtrl.