* The idea is to move the callback based mechanism into a derived
class. The objects can be composed to create working systems.
* The BMediaClient class supply RegisterInput/RegisterOutput
and BeginInput/BeginOutput is moved to BSimpleMediaClient.
* Various minor fixes.
* The BMediaClient is an higher level API to the media_kit. It
corresponds to what the layout API was for the interface_kit.
The main idea is to allow the developer concentrate only on
higher level details and avoiding handle with the tricky parts
of the media_kit. At the same time the general purpose node that
is implemented inside would allow implementing the best techniques
around thus at the same time reducing code duplication and increasing
efficiency.
* BMediaClient is WIP, this is the initial merge of the branch.
The initial development stone was set long time ago and walked
through various design/implementation phases.
