gracefully handle helper method calls to objects that are not beeing controlled,...

gracefully handle helper method calls to objects that are not beeing controlled, added test case for that

Original commit message from CVS:
* check/gst-libs/controller.c: (GST_START_TEST),
(gst_controller_suite):
* docs/gst/tmpl/gstcaps.sgml:
* docs/gst/tmpl/gstghostpad.sgml:
* docs/gst/tmpl/gstquery.sgml:
* docs/gst/tmpl/gstutils.sgml:
* libs/gst/controller/gst-helper.c: (gst_object_set_controller),
(gst_object_sink_values), (gst_object_get_value_arrays),
(gst_object_get_value_array):
gracefully handle helper method calls to objects that are not beeing
controlled, added test case for that