This patch makes it possible to dinamically close the current segment
and step to the next one by introducing command handling capabilities
into the filter. This new feature is very usefull when working with
real-time sources or live streams as source. Combinig usage with zmqsend
tool you can interactively end the current segment and step to next one.
Signed-off-by: Bela Bodecs <bodecsb@vivanet.hu>