Gqrx SDR 2.13

• Stereo option for UDP streaming.
• Script to generate AppImage.
• Allow scroll wheel direction to be inverted.
• Fixed FM de-emphasis causing audio to be 20 dB quieter than it should be.
• Fixed FM de-emphasis applied incorrectly in WFM stereo receiver.
• Update waterfall time resolution when FFT settings are changed.
• Update waterfall time resolution when window is resized.
• Restore waterfall time span between sessions.
• Fixed FFT buffer overlap calculation.
• Fixed crash when launching without device connected.
• Fixed crash when setting invalid RF gains.
• Fixed audio panadapter / waterfall slider direction.
• Clear FFT averages when changing FFT size.
• Fixed crash when source block doesn't support IQ balancing.
• Fixed bookmark labels in FFT draw over each other.
• Improved DSP and FFT performance.
• Improved panadapter & waterfall performance.
• Smooth panadapter & waterfall redrawing.
• Better default values for various settings.
• Audio waterfall colormap matches I/Q waterfall.
• Use all available display space for panadapter & waterfall.
• Updated RDS decoder.
• More Airspy HF+ sample rates added.