aggregator: expose force_live API and add "force-live" property to audio/video aggregator base classes
aggregator: Implement force_live API
Setting force_live lets aggregator behave as if it had at least one of its sinks connected to a live source, which should let us get rid of the fake live test source hack that is probably present in dozens of applications by now.
- Expose API for subclasses to set and get force_live
- Expose force-live properties in GstVideoAggregator and GstAudioAggregator
- Adds a simple test
Edited by Mathieu Duponchelle