Enhanced Bessel and Butterworth filters init
Trial at getting Chebyshev type 1 working
Python wrappers for Chebyshev type 1
Fixing Chebyshev type 1 (except band stop)
Band stop is in fact OK due to ripples
Small Chebyshev comparison with scipy example
Chebyshev type 2 seem OK
Merge branch 'feature/Chebyshev' into develop