RTL radio spectrum scanner Toy project to learn Rust

Notes: Integer FFT: http://www.jjj.de/fft/fftpage.html

Psd: https://www.mathworks.com/help/signal/ug/power-spectral-density-estimates-using-fft.html

Goos quality analyzer: http://www.kerrywong.com/2014/11/16/testing-an-rtl-sdr-spectrum-analyzer/

DC removal: http://www.embedded.com/design/configurable-systems/4007653/DSP-Tricks-DC-Removal

TODO: Chart: Elasic size Grid Axis labels * Switch to SoapySDR api * SIMD Compare performance/respurces to fftw * Events and rendering are polled in tight loop. Need to rework to use events_loop.run_forever() and inject charts update statistics. * FFTW is in f64 by default, it would be nice to do f32 arithmetics instead or even in integrer domain