High performant TCP server for rtl-sdr.

Key features:
* Share available RF bandwidth between several independent clients:
- Total bandwidth can be 2016000 samples/sec at 436,600,000 hz
- One client might request 48000 samples/sec at 436,700,000 hz
- Another client might request 96000 samples/sec at 435,000,000 hz
* Several clients can access the same band simultaneously
* Output saved onto disk or streamed back via TCP socket
* Output can be gzipped (by default = true)
* Output will be decimated to the requested bandwidth
* Clients can request overlapping RF spectrum
* Rtl-sdr starts only after first client connects (i.e. saves solar
power &etc). Stops only when the last client disconnects