Allow device string modifcation for RTL-SDR dongles (to enable bias-t)
At least two users (myself and W5SAT) have discovered that using the RTL-SDR.com V3 bias-t enabling switch via the "pre-observation script" option fails to enable the bias-t of the dongle. This appears to be because when the dongle is initialized, the state of the bias-t is returned to its default - which is apparently "off". This can be replicated in GQRX, as well. However, the solution in GQRX is to add ",bias=1" (I believe, can't remember the exact modification) to the device string in the device settings. This allows GQRX to turn to bias-t on during the device initialization (I believe, I'm not a code guy). Can this modification be added to gr-satnogs so that we can utilize the bias-t?