Add sample rates for RF Space SDR-IQ and SDR-IP.

Patch from Dimitri Stolnikov.
Updated news and readme files.
Replaced deprecated string function

.toAscii() is deprecated (and broke my build). See Qt docs.
Merge pull request #142 from 4ZM/master

Replaced deprecated string function
Add support for reading signal strength through TCP.
Add mode selection to TCP interface.
Do not crash if you don't have permissions to write to a file
Merge pull request #149 from benburkhart1/master

Do not crash if there is an error creating the wave sink (e.g. permissions).
Add support for Airspy sample rates.

Patch received from Dimitri Stolnikov.
Update callsign for Göran Weinholt.
Add command line option to list existing configurations.