Update copyright year in the doc footer (2015 → 2016)

Author: ohld

doc/conf.py

@@ -65,7 +65,7 @@
 
 # General information about the project.
 project = u('scikit-learn')
-copyright = u('2010 - 2015, scikit-learn developers (BSD License)')
+copyright = u('2010 - 2016, scikit-learn developers (BSD License)')
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the