REL bump version to 0.16.1, change in documentation.rst, add to news

REL Version 0.16.0 (adjust __version__, links in docs)

0.16.X branching, version 0.16b1

Merge pull request scikit-learn#4352 from amueller/issue-4297-infinit…

…e-isotonic_bak

[MRG + 2] Adding fix for issue scikit-learn#4297, isotonic infinite loop

Release 0.15.2

MAINT preparing the 0.15.1 release

REL: Release 0.15.0

Tag for the 0.15.0b2 release

MAINT remove residual sparsefuncs*.so when compiling

The sparsefuncs -> sparsefuncs_fast rename in bbb8f1d has caused a lot of errors being reported due to dirty working directories. This attempts to avoid that.

Branching 0.15.X to prepare the 0.15.0b1 release