Added API to pannable are in order to get its adjustments. We added two properties...

Added API to pannable are in order to get its adjustments. We added two properties to manage the values we had in the private structure.

* src/hildon-pannable-area.c:
	(hildon_pannable_area_class_init): Added hadjustment and
	vadjustment properties in order to expose horizontal and vertical
	adjustment.
	(hildon_pannable_area_get_property),
	(hildon_pannable_area_set_property): Added code to handle the new
	properties
	(hildon_pannable_area_get_hadjustment),
	(hildon_pannable_area_get_vadjustment): API functions to get the
	adjustments
	* src/hildon-pannable-area.h:
	(hildon_pannable_area_get_hadjustment),
	(hildon_pannable_area_get_vadjustment): API functions to get the
	adjustments