FIX: windows test failures in test_ransac
Fixing classes.rst
Merge pull request #3169 from mjbommar/issue-3167-eradicate-todense

PR re: issue 3167 to eradicate .todense()
Adding Notes section to img_to_graph and grid_to_graph re: np.matrix->np.ndarray
Adding what's new item for sklearn.feature_extraction.image np.ndarray changes
Merge pull request #3193 from mjbommar/issue-3167-eradicate-todense

Minor docstring and What's New changes for issue 3167
Workaround for andrewclegg/snake-charmer#12
Fixed typo
Merge pull request #3196 from andrewclegg/master

Fix for Python 3.x race condition causing "RuntimeError: dictionary changed size during iteration"
Switching from np to math for scalar float ops
Merge remote-tracking branch 'upstream/master' into isotonic-increasing-auto
Merge pull request #3157 from mjbommar/isotonic-increasing-auto

[MRG] Determine IsotonicRegression ``increasing`` by Pearson or Spearman corr rho
Explicitly invoke the Python interpreter.
Use double backticks.
Remove extraneous period.
Explain the -1 Python syntax.
Additional docstring fixes for issue #3167
Merge pull request #3197 from mjbommar/issue-3167-eradicate-todense

Additional fixes for .todense() / issue #3167
Merge branch 'master' of https://github.com/scikit-learn/scikit-learn
Adding tests to handle out_of_bounds parameter.