Complex coefficients of wavelet transform

[refactoriel]

Hi @jgraving

great toolbox, works out-of-the-box for me. I see that you're taking the magnitude of the complex coefficients from the wavelet transform in

behavelet/behavelet/morlet.py

Line 166 in 24b59f4

convolved = backend.abs(convolved) # use the norm of the complex values

Would it be possible to add an option to retrieve the complex values instead? Maybe some clustering algorithms can make use of the phase as well.

Best,
Daniel