Add and bind Object.locateSlot.
Add and bind Object.locateSlot.

	* src/object/object-class.cc: (object_class_LocateSlot) call
	  slot_locate, return nil_class on failure.

Signed-off-by: Matthieu Nottale <73d816bf5a7c98ca49eb19b3fa4036e0ae653e5f@gostai.com>

urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi