implement SpectralAngleMapper (SAM)

[Andreas Janz]

Requested by @Agustin Lobo .

Fits a SAM classifier from a classification dataset (which can be a categorized spectral library with endmembers).

Maybe use PySptools: https://pysptools.sourceforge.io/classification.html?highlight=angle#spectral-angle-mapper-sam

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[Andreas Janz]

Or better use Scikit-Learn classifier pipeline:

1. Normalize features into angle space: https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.Normalizer.html
2. Use Nearest Neighbor Classifier : https://scikit-learn.org/stable/modules/generated/sklearn.neighbors.KNeighborsClassifier.html#sklearn.neighbors.KNeighborsClassifier

@Agustin Lobo that would do it, right?

[Andreas Janz]

Done

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[Andreas Janz]

resolves #914

→ <<cset 9285a0c452ab>>

[Agustin Lobo]

Will check as soon as a new dev version be available as zip file