jitterbuffer: assume a full buffer when eos

Rework the logic to make buffering messages a little, make sure we
don't make the same message multiple times.
Consider the buffer full when EOS was received.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=728017

Conflicts:
	gst/rtpmanager/gstrtpjitterbuffer.c
Update .po files
Release 1.2.4
jitterbuffer: improve EOS handling

Make a new method to disable the jitterbuffer buffering.
Rework the update_estimated_eos() method. Calculate how much time
there is left to play. If we have less than the delay of the
jitterbuffer, we disabled buffering because we might never be able to
fill the complete jitterbuffer again.
If we receive an EOS event, disable buffering. We will drain the
buffer and eventually push the EOS event out.
When we reach the estimated NPT timeout and we didn't receive an EOS
event, make one and queue it so that it can be pushed.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=728017

Conflicts:
	gst/rtpmanager/gstrtpjitterbuffer.c
Add last commit to the RELEASE notes and ChangeLog
gstrtph264pay: Reset sps pps variable when state change.

Reset last_spspps and sps/pps arrays  when state transition
GST_STATE_CHANGE_PAUSED_TO_READY.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=726015