Music lib support

This pull request implements methods to retrieve music library like the search folders, albums, artists, tracks etc.

It consists of 4 commits:
18b adds the main methods for retrieving all the different kinds of information
1f4 is a convinience method in utils.py to convert camelcase (tag name) string to small letters and underscores
5f1 adds 8 convience methods (that removes the search type argument from the main method), one for each of the searches
68f adds the propser credits for protocol research to the Janos project, form whom I have gathered the information necessary to implement these methods.

These changes can be reviewed just as easily as one combined diff or as each of the commits on their own.

Comments are welcome.

Regards Kenneth