Adding string={pearson, spearman} option to increasing argument in IsotonicRegression.
Adding increasing and decreasing tests for both Pearson and Spearman increasing argument options
DOC : fix alpha docstring in dict learning
Refactoring increasing_bool set into _check_increasing method
PEP8ing isotonic tests
PEPing isotonic regression
DOC : really fix alpha docstring in dict learning
Docstring style changes
Revert "DOC : really fix alpha docstring in dict learning"

This reverts commit 645863e0f26fd0ed568972f1373d61e1bb10261a.

@agramfort: sorry: a better read of the code told me that it was
transform_alpha used by the OMP. So alpha is indeed always a float
FIX unused pos_label parameter in metrics.precision_recall_curve
Change arguments to increasing={'auto', True, False} and default to 'auto'; implement Fisher transform and warning on 0 \in CI
Adding test for CI check and removing Spearman/Pearson-specific tests.
Minor docstring cleanup
Minor docstring cleanup
Docstring fix
Replacing the non-test .todense() methods with .toarray()
Replacing the test .todense() methods with .toarray()
Improving tests to affirm no CI warnings are thrown when appropriate
Matching CI calculation and docstring with reference
Fixing docstring