Added one stage to the CIC filter. Now properly recording.

Signed-off-by: Riccardo Binetti <punkerbino@gmail.com>
Changed interface to the Microphone Class.

Now the class will accept a callback and it will call it when a buffer is ready.

Signed-off-by: Riccardo Binetti <punkerbino@gmail.com>
Adapted player to the new Microphone interface.

Signed-off-by: Riccardo Binetti <punkerbino@gmail.com>