Escape key focuses nothing

Pressing the escape key will no longer focus the tabs, but instead will
focus nothing.  I think this is better visually.

ocarina/components/entry.py

@@ -22,7 +22,7 @@ class FilterEntry(gtk.Entry):
 def key_press(widget, event):
 	name = gtk.gdk.keyval_name(event.keyval)
 	if name == "Escape":
-		body.body.grab_focus()
+		ocarina.window.window.set_focus(None)
 		return
 	if filter.is_focus():
 		return