Reviewed the threading handling of the pannable widget, we have used the gdk_threads_...

Reviewed the threading handling of the pannable widget, we have used the gdk_threads_add_timeout function instead of the usual glib handlers. This avoids some problems with the threads.

* src/hildon-pannable-area.c (hildon_pannable_area_grab_notify),
	(hildon_pannable_area_initial_effect),
	(hildon_pannable_area_scroll_indicator_fade),
	(hildon_pannable_area_button_press_cb),
	(hildon_pannable_area_timeout),
	(hildon_pannable_area_motion_notify_cb),
	(hildon_pannable_area_button_release_cb),
	(hildon_pannable_area_scroll_cb),
	(hildon_pannable_area_scroll_to): Removed the
	GDK_THREAD_ENTER/LEAVE and replaced g_timeout_add with
	gdk_threads_add_timeout.

	Fixes: NB#89541 (Crash in pannable area when closing picker dialog)