Musicase Support

* Added support for Musicase (http://musicase.me/)

Screenshots
https://drive.google.com/file/d/0B_2eSXlwVD17ZGxVS0NhTjY0cEE/view?usp=sharing
https://drive.google.com/file/d/0B_2eSXlwVD17SWF1aDFzN1pLMUk/view?usp=sharing
https://drive.google.com/file/d/0B_2eSXlwVD17R19objZESWVfTXM/view?usp=sharing
As above set `artist`, `track`, `album` with the `currect` variables.