#785 Wavelet operations

[Jeremy Faden]

I've been meaning to add some wavelet transformations to provide functionality similar to pywavelets. Sadie would use this right away.

Some resources:

https://towardsdatascience.com/the-wavelet-transform-e9cfa85d7b34
https://github.com/PyWavelets/pywt
https://pywavelets.readthedocs.io/en/latest/