Add scalar processing for MedianFilter (#85)

Bugfix IRFFT for semiprime n (#83)

Update besseli0 function for kaiser window (#82)

Move MAFilter to public interface. Update tests. Update docs.

Use binary tree for MAFilter (#81)

Hide IFFT to factory with caching (#77)

Fix sfinae for cmplx_t convertions

dont cache FFT of size 3

Add fftshift, circshift, sqrt functions

reduce FFT table size