Changes to work with py2app

Changes necessary to make successfull packaging possible on OSX with
py2app.
Update to include OpenCV modules
Fixed typo in tab_widget.py

Match tab_name value set in start_new_widget.py.
Do not use `numbers` module, because it is not available on Android
Merge remote-tracking branch 'dschreij/master' into playground
Merge remote-tracking branch 'rsprouse/master' into playground