matplotlib#2150 wip - added change log

Author: sfroid

CHANGELOG

@@ -1,5 +1,7 @@
 2014-03-24 Changed the behaviour of axes to not ignore leading or trailing
-           patches of height 0 while calculating the x and y axis limits.
+           patches of height 0 (or width 0) while calculating the x and y
+           axis limits. Patches having both height == 0 and width == 0 are
+           ignored.
 
 2014-03-17 Bug was fixed in append_axes from the AxesDivider class would not
            append axes in the right location with respect to the reference