Update to mean shit clustering narrative documentation.
Update to docstring of meanshift
docstring of module
Fix typos found by Alexandre
DOC: more context in embedded code

Fixes #2816
DOC: more robust compilation and CSS
Merge pull request #2768 from robertlayton/meanshiftdoc

MRG: Update to Mean Shift clustering documentation
Minor doc example fix
Merge pull request #2820 from ankit-maverick/issue2819

Minor DecisionTree doc example fix