ges-source-clip: fixed return of duration setter
In general, brought the behaviour of the start
, duration
and
inpoint
setters in line with each other. In particular:
- fixed return value the GESSourceClip
duration
setter - changed the GESClip
start
setter - fixed the inpoint callback for GESContainer
- changed the type of
res
in GESTimelineElement to be gint to emphasise that the GES library is using the hack that a return of -1 from klass->set_duration means no notify signal should be sent out.
Also added a new test for clips to ensure that the setters work for
clips within and outside of timelines, and that the start
, inpoint
and duration
of a clip will match its children.