Since GtkIconViews a11y implementation only takes text from
GtkCellRendererText::text, derive ShellSearchRenderer from
GtkCellRendererText and set the text property. Now orca
reads the search results nicely.
While we do want to match case-insensitively, we don't want to
display the search result in all-lowercase. This patch is probably
not quite utf8-ly correct.
http://bugzilla.gnome.org/show_bug.cgi?id=634923