Refactoring, small improvements, and cleaning notation of IsotonicRegression
DOC more complete coverage of API linking in examples

Previously ignored non-plot files.

Avoids some link over/undergeneration
TST add test for name identification in RST generation
TST avoid nose running setup() in gen_rst.py
TST add sphinxext to testing
Changing docs from "vector" to "1d array"
Fix Machine Learning for NeuroImaging in Python link.
Merge pull request #3254 from laurentluce/presentations-links-fix

Fix "Machine Learning for NeuroImaging in Python" link.
TST remove dependencies for testing sphinxext
DOC: fix 2 covariance examples rst math markup.

Some formulas in plot_mahalanobis_distances and
plot_robust_vs_empirical_covariance were not correctly rendered by sphinx
as some characters were not properly escaped. This is fixed by setting the
docstrings as raw string using r"""

There was also missing braces for the number of features and samples subscript.
Branching 0.15.X to prepare the 0.15.0b1 release
TST test interaction features outside doctest
Minor fixes in the docs
Fix some fun column span alignment errors.
Reverting array X to vector x rename
DOC fix deprecation in CD
DOC missing verb in README
Merge pull request #3260 from larsmans/cd-deprecation

[MRG] fix faulty deprecation in CD
DOC : clarify error message in _binary_roc_auc_score
TST silence spectral test/test warning message