ext/theora/theoraenc.c: Mark the last packet with an EOS flag which is not really...

ext/theora/theoraenc.c: Mark the last packet with an EOS flag which is not really needed in gstreamer.

Original commit message from CVS:
* ext/theora/theoraenc.c: (gst_theora_enc_class_init),
(theora_enc_sink_link), (theora_push_packet), (theora_enc_chain),
(theora_enc_change_state), (theora_enc_set_property),
(theora_enc_get_property):
Mark the last packet with an EOS flag which is not really needed
in gstreamer.
Do some better video framerate initialisation.
Update the buffer timestamp.