implements an FFT engine based on the betaflight feature using ARM hardware accelerated CMSIS library
make the FFT feature optional
add dynamic gyro windows
add quinns and candans estimators and record in DSP state
disable DSP for boards with limited flash
calculate power spectrum rather than amplitude
start/analyse version of analysis to support threading
allocate memory in a specific region
constrain window size by CPU class
control inclusion of DSP based on board size
Andrew Tridgell
Andy Piper