[DOC] add release dates for each version on whats_new page (scikit-learn#7225)

Author: b-carter

doc/whats_new.rst

@@ -9,6 +9,8 @@ Release history
 Version 0.18
 ============
 
+**In Development**
+
 Changelog
 ---------
 
@@ -442,6 +444,8 @@ API changes summary
 Version 0.17.1
 ==============
 
+**February 18, 2016**
+
 Changelog
 ---------
 
@@ -482,6 +486,7 @@ Bug fixes
 Version 0.17
 ============
 
+**November 5, 2015**
 
 Changelog
 ---------
@@ -913,6 +918,8 @@ API changes summary
 Version 0.16.1
 ===============
 
+**April 14, 2015**
+
 Changelog
 ---------
 
@@ -945,6 +952,8 @@ Bug fixes
 Version 0.16
 ============
 
+**March 26, 2015**
+
 Highlights
 -----------
 
@@ -1411,6 +1420,8 @@ API changes summary
 Version 0.15.2
 ==============
 
+**September 4, 2014**
+
 Bug fixes
 ---------
 
@@ -1453,6 +1464,8 @@ Bug fixes
 Version 0.15.1
 ==============
 
+**August 1, 2014**
+
 Bug fixes
 ---------
 
@@ -1492,6 +1505,8 @@ Bug fixes
 Version 0.15
 ============
 
+**July 15, 2014**
+
 Highlights
 -----------
 
@@ -2023,6 +2038,8 @@ List of contributors for release 0.15 by number of commits.
 Version 0.14
 ===============
 
+**August 7, 2013**
+
 Changelog
 ---------
 
@@ -2406,6 +2423,8 @@ List of contributors for release 0.14 by number of commits.
 Version 0.13.1
 ==============
 
+**February 23, 2013**
+
 The 0.13.1 release only fixes some bugs and does not add any new functionality.
 
 Changelog
@@ -2452,6 +2471,8 @@ List of contributors for release 0.13.1 by number of commits.
 Version 0.13
 ============
 
+**January 21, 2013**
+
 New Estimator Classes
 ---------------------
 
@@ -2790,6 +2811,8 @@ List of contributors for release 0.13 by number of commits.
 Version 0.12.1
 ===============
 
+**October 8, 2012**
+
 The 0.12.1 release is a bug-fix release with no additional features, but is
 instead a set of bug fixes
 
@@ -2835,6 +2858,8 @@ People
 Version 0.12
 ============
 
+**September 4, 2012**
+
 Changelog
 ---------
 
@@ -3028,6 +3053,8 @@ People
 Version 0.11
 ============
 
+**May 7, 2012**
+
 Changelog
 ---------
 
@@ -3263,6 +3290,8 @@ People
 Version 0.10
 ============
 
+**January 11, 2012**
+
 Changelog
 ---------
 
@@ -3448,6 +3477,8 @@ The following people contributed to scikit-learn since last release:
 Version 0.9
 ===========
 
+**September 21, 2011**
+
 scikit-learn 0.9 was released on September 2011, three months after the 0.8
 release and includes the new modules :ref:`manifold`, :ref:`dirichlet_process`
 as well as several new algorithms and documentation improvements.
@@ -3685,6 +3716,8 @@ People
 Version 0.8
 ===========
 
+**May 11, 2011**
+
 scikit-learn 0.8 was released on May 2011, one month after the first
 "international" `scikit-learn coding sprint
 <https://github.com/scikit-learn/scikit-learn/wiki/Upcoming-events>`_ and is
@@ -3785,6 +3818,8 @@ People that made this release possible preceded by number of commits:
 Version 0.7
 ===========
 
+**March 2, 2011**
+
 scikit-learn 0.7 was released in March 2011, roughly three months
 after the 0.6 release. This release is marked by the speed
 improvements in existing algorithms like k-Nearest Neighbors and
@@ -3876,6 +3911,8 @@ People that made this release possible preceded by number of commits:
 Version 0.6
 ===========
 
+**December 21, 2010**
+
 scikit-learn 0.6 was released on December 2010. It is marked by the
 inclusion of several new modules and a general renaming of old
 ones. It is also marked by the inclusion of new example, including
@@ -3976,6 +4013,8 @@ People that made this release possible preceded by number of commits:
 Version 0.5
 ===========
 
+**October 11, 2010**
+
 Changelog
 ---------
 
@@ -4088,6 +4127,8 @@ number of commits:
 Version 0.4
 ===========
 
+**August 26, 2010**
+
 Changelog
 ---------