Added better logging for channel changes.
Performance enhancement via recvmmsg().

Use recvmmsg() in order to read multiple packets with one system call.
This improves performance, especially in have loaded areas when catching up
a log of queued packets.

Original patch tweaked and optimized by Rolf Ahrenberg.
Preliminary documentation for used logging modes.
Deduplicated pid listings.
Added RTCP packet logging.
Renamed threads and ringbuffers.
Fixed a race condition while updating pids.
Fixed the default logging mode in a DEBUG build.
Fixed reconnection.
Reformatted some info messages.
Added a SCAN command into the SVDRP interface.
Removed DVB-C model quirks from OctopusNet. The firmware version 1.0.40 looks correct.