- Elements can now send events to their parent.

- Elements can now send events to their parent.

Original commit message from CVS:
- Elements can now send events to their parent.
- remove the g_signals from the core for parent<->child communication
- the application can easily get element info by listening for an event
signal from the toplevel bin.
- added gst_element_info()/_error().
- fakesrc and fakesink use the info event instead of g_print.
- GST_TYPE_* causes segfaults with elect fence, rever to G_TYPE_POINTER
until we know what's wrong.
- various leaks fixed wrt element destroy.
- The object that created the event is now stored as GST_EVENT_SRC