Merge pull request #2797 from cli248/fix-DeprecationWarning

Fix deprecation warning in Python 3
DOC: more context in embedded code

Fixes #2816
DOC: more robust compilation and CSS
Add prototype for validation curve
Add documentation and tests
Improve test coverage

... to 99%
Improve interface and documentation
Mocks inherit from BaseEstimator
Correct docstring
Add narrative documentation
Improve documentation

* add images
* add link to API doc
* change order
Fix link to validation curve
Add example with polynomial regression
Correct and improve documentation
Improve phrasing
Rephrase sentence
Simplify first part of the documentation
Merge pull request #2768 from robertlayton/meanshiftdoc

MRG: Update to Mean Shift clustering documentation
COSMIT remove unused imports and variables
Minor doc example fix