Update jukebar.py
Update jukebar.py

Workarounds the Class not found JavaException refs:
    - https://github.com/kivy/pyjnius/issues/137
    - https://github.com/kivy/pyjnius/issues/223
    - http://stackoverflow.com/a/27943091/185510

jeremyklelifa/Jukebar,jeremyklelifa/Jukebar