Re-organize API.

EekGtkKeyboard is now a subclass of GtkWidget not EekKeyboard.  Widget
creation is done as follows:

layout = eek_xkl_layout_new (...);
keyboard = eek_keyboard_new (layout, 640, 480);
widget = eek_gtk_keyboard_new (keyboard);

Broken Clutter support is temporarily disabled.

eek/eek-xkb-layout.c

@@ -325,6 +325,7 @@ eek_xkb_layout_real_apply (EekLayout *layout, EekKeyboard *keyboard)
                                                 g_direct_equal,
                                                 NULL,
                                                 outline_free);
+
     create_keyboard (EEK_XKB_LAYOUT(layout), keyboard);
 }