add 0.2.1 whatsnew

Author: wholmgren

docs/sphinx/source/whatsnew.rst

@@ -6,5 +6,6 @@ What's New
 
 These are new features and improvements of note in each release.
 
+.. include:: whatsnew/v0.2.1.txt
 .. include:: whatsnew/v0.2.0.txt
 .. include:: whatsnew/v0.1.0.txt

docs/sphinx/source/whatsnew/v0.2.1.txt

@@ -0,0 +1,18 @@
+.. _whatsnew_0210:
+
+v0.2.1 (July 13, 2015)
+-----------------------
+
+This is a minor release from 0.2.1. It includes a large number of bug fixes
+for the IPython notebook tutorials.
+We recommend that all users upgrade to this version.
+
+Bug fixes
+~~~~~~~~~
+
+* Fix incorrect call to Perez irradiance function (:issue:`76`)
+
+Contributors
+~~~~~~~~~~~~
+
+* Will Holmgren