Mask unmixing

[ntessore]

We need to decide if we want to move the code for mask unmixing (deconvolution) into Heracles.

Either way, the actual unmixing code should be used for the jackknife covariance.

[JaimeRZP]

I feel brave about doing this now.
My private code is already a library of which we really have to bring in 3 methods.

[JaimeRZP]

Natural Unmxing

PolSpice Plus

PolSpice Minus

[JaimeRZP]

I have broken down this big project in three two PRs:

• gh-256: inversion #303
• gh-256: unmixing tutorial #304

[JaimeRZP]

Great success @ntessore !