+ Fix tests (starting using GESTestClip instead of GESCustomClip)
Now the height is not only growing, but can also go down, as the value
is just simply computed
API:
GESContainer::compute_height virtual method
... Not the other way round.
+ Add and enhance debugging info on the way
The user should not be responsible for removing the GESTrackElements from
GESTracks, instead, removing it from a GESClip should imply removing
it from any GESTrack it is in.
This patch changes sensibly the behaviour when we remove a
GESTrackElement from a GESTrack, not remoing it from the GESClip it is
in. *But*, users should never remove a GESTrackElement from a GESTrack
anyway. The testsuite has been updated to that new behaviour.
+ Fix tests as necessary (Do not use agingtv as it can be "applied" on any TrackType
and is not representative of what happens IRL)
We already had the infrastructure so the user can have the control over where to add
the elements (through the "select-track-for-object" signal). We now make use of that
signal everytime a GESClip is added to a GESTimelineLayer. This make user's life easier,
and object responsability clearer.
