Added information about backend renderer issue on MacOS

README.md

@@ -288,3 +288,6 @@ Todo/Issues/Wishlist
 
 * If you use Anaconda on Windows, you might need to set PYTHONHOME to Anaconda home directory and QT_QPA_PLATFORM_PLUGIN_PATH to %PYTHONHOME%Library/plugins/platforms. The latter is for especially when you get the error which says 'This application failed to start because it could not find or load the Qt platform plugin "windows"
 in "".'
+
+* MacOS: `Unable to import matplotlib.pyplot`. Cause: In mac os image rendering back end of matplotlib (what-is-a-backend to render using the API of Cocoa by default). There is Qt4Agg and GTKAgg and as a back-end is not the default. Set the back end of macosx that is differ compare with other windows or linux os.
+Solution is discribed [here](https://stackoverflow.com/questions/21784641/installation-issue-with-matplotlib-python?noredirect=1&lq=1), additional information can be found there too(see links in answers).