Fixes for choosing files from search results

Cherry pick cb55418831fa4e167c11a86dd170376a18bc978a from git://github.com/sehmaschine/django-filebrowser.git, which fixes  https://github.com/sehmaschine/django-filebrowser/issues/135

Add a fix for https://github.com/sehmaschine/django-filebrowser/issues/150