FIX remove confusing BaseEstimator.__str__
Update to mean shit clustering narrative documentation.
Update to docstring of meanshift
docstring of module
Fix typos found by Alexandre
ENH faster heapsort in trees

Uses the heapsort version that I'm familiar with: linear-time heapify
followed by n delete-min operations. Also cache-friendlier by copying
active features into a temporary array.

Random forest training time on covertype:
now     34.4123s
before  60.1179s
ENH introsort in tree learner

Covertype w/ random forest training time down to 29.0857s.
ENH Make PresortBestSplitter cache friendly + cosmetics
Proper centering of alpha_grid for sparse matrices
FIX: Normalize=True
update what's new
Merge pull request #2747 from larsmans/tree-sort

[MRG] faster sorting in trees; random forests almost 2× as fast
clarify what's new
fix converting an array with ndim > 0 to an index DeprecationWarning
using floor division in python3
Added docstrings for model attributes in LabelPropagation and LabelSpreading
Merge pull request #2799 from charlescearl/charles-label-prop-doc-updates

Added docstrings for model attributes in LabelPropagation and LabelSprea...
Fixed documentation on sklearn/tree
Merge pull request #2800 from eltermann/doc-fix-tree

Fixed documentation on sklearn/tree
handle the case when length of sign changed coefficients is greater than 1 in LARS algorithm