List of ideas, possible improvements

• Changing frequency with the QSpinBox-es is quite difficult.
• TX modulation could be changed on the fly.
• We could have a "TEST TONE" button.
• We would also need a MIC gain slider.
• Some microphones need additional gain, could be added with csdr gain_ff or something.
• QSpinBox for the frequency offset between the transmitter and the receiver.
• Transmit CW by reading the key connected to GPIO.
• Waterfall contrast setting