Packaging:
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Documentation with sphinx
Document methods with paper references
unit-tests

New features:
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Add NAE, NRAE
Add "measures for evaluating ordinal"?
Add datasets for topic.
Do we want to cover cross-lingual quantification natively in QuaPy, or does it make more sense as an application on top?

Current issues:
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In binary quantification (hp, kindle, imdb) we used F1 in the minority class (which in kindle and hp happens to be the
negative class). This is not covered in this new implementation, in which the binary case is not treated as such, but as
an instance of single-label with 2 labels. Check
Add automatic reindex of class labels in LabelledCollection (currently, class indexes should be ordered and with no gaps)
OVR I believe is currently tied to aggregative methods. We should provide a general interface also for general quantifiers
Currently, being "binary" only adds one checker; we should figure out how to impose the check to be automatically performed
Add random seed management to support replicability (see temp_seed in util.py).

Improvements:
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Explore the hyperparameter "number of bins" in HDy
Rename EMQ to SLD ?
Parallelize the kFCV in ACC and PACC?
Parallelize model selection trainings
We might want to think of (improving and) adding the class Tabular (it is defined and used on branch tweetsent). A more
    recent version is in the project ql4facct. This class is meant to generate latex tables from results (highligting
    best results, computing statistical tests, colouring cells, producing rankings, producing averages, etc.). Trying
    to generate tables is typically a bad idea, but in this specific case we do have pretty good control of what an
    experiment looks like. (Do we want to abstract experimental results? this could be useful not only for tables but
    also for plots).

Checks:
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How many times is the system of equations for ACC and PACC not solved? How many times is it clipped? Do they sum up
    to one always?
Re-check how hyperparameters from the quantifier and hyperparameters from the classifier (in aggregative quantifiers)
    is handled. In scikit-learn the hyperparameters from a wrapper method are indicated directly whereas the hyperparams
    from the internal learner are prefixed with "estimator__". In QuaPy, combinations having to do with the classifier
    can be computed at the begining, and then in an internal loop the hyperparams of the quantifier can be explored,
    passing fit_learner=False.
Re-check Ensembles. As for now, they are strongly tied to aggregative quantifiers.
Re-think the environment variables. Maybe add new ones (like, for example, parameters for the plots)
Do we want to wrap prevalences (currently simple np.ndarray) as a class? This might be convenient for some interfaces
    (e.g., for specifying artificial prevalences in samplings, for printing them -- currently supported through
    F.strprev(), etc.). This might however add some overload, and prevent/difficult post processing with numpy.
Would be nice to get a better integration with sklearn.