summary: fix xml in gstreamer 1) make clear distinction between loading xml that actually creates objects and loading...

Original commit message from CVS:
summary: fix xml in gstreamer

1) make clear distinction between loading xml that actually creates objects and loading xml that just
synchronizes properties with objects. moved most of gst_element_restore_thyself functionality to
gst_xml_make_element. this new function name can change if it sucks.
2) many various fixes. createxml and runxml work now.
3) doc updates.
4) GstSignalObject is stil broken. i have no idea what it's supposed to do.