Remove the context again, adding an extra layer of refcounting and object
creation to manage an array is too complicated and inefficient. Use a simple
array again.
Also implement event updates when calling gst_pad_chain() and
gst_event_send_event() directly.
This reverts commit 9ef1346b1f.
Way to much for one commit and I'm not sure we want to get rid of the pad caps
just like that. It's nice to have the buffer and its type in onw nice bundle
without having to drag the complete context with it.