TimeSide Ccore ProcessPipe: Solve #8 by providing a more user-friendly implementation...

TimeSide Ccore ProcessPipe: Solve #8 by providing a more user-friendly implementation than previous solution

- The frames can be stored in the `ProcessPipe` frames_stack attribute if the pipe is run with argument 'stack=True' (default stack=False)
- The ProcessPipe is now linked to its processors through the processor self.process_pipe attribute (this avoid confusion with `decoder.pipe` or `decoder.pipeline` (-> reflect this change in all analyzers)
- After the process, during the release every processors of the pipe are removed from the pipe (except the decoder)