Synchronizing the LimeSDR transmitter and receive using timestamps

As Josh noted, there will be a delay, but it should be consistent across runs for a given configuration. From what I recall things like the transceiver in the Osmocom GSM stack need to be configured with a delay figure, in order for it to work reliably. However, this is hard coded for each type of SDR hardware.

@Garmus, perhaps you could comment further on configuration steps etc.