fix wrong confidence interval
Remove HMM examples

Fixes #2646
Adding string={pearson, spearman} option to increasing argument in IsotonicRegression.
Adding increasing and decreasing tests for both Pearson and Spearman increasing argument options
Merge pull request #3156 from IvicaJovic/fixes

DOC Fix wrong confidence interval
FIX: use clip(0) instead of abs()

This removes spurious tiny negatives from the output of eig.
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()