added the unit tests for changing units in the main directory

Author: azmimoha

matplotlibrc.template

@@ -29,7 +29,7 @@
 # You can also deploy your own backend outside of matplotlib by
 # referring to the module name (which must be in the PYTHONPATH) as
 # 'module://my_backend'
-backend      : %(backend)s
+backend      : Qt4Agg
 
 # If you are using the Qt4Agg backend, you can choose here
 # to use the PyQt4 bindings or the newer PySide bindings to