Initial checkin of config module

--HG--
extra : rebase_source : 0c94fc536f051517fc3fc26220ef38fa3acaa3d0
Refactoring Cache classes

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rename : unittest/test_utils.py => unittest/test_cache.py
extra : rebase_source : 99262db633eed43c909e6804ecff55a2b5d3eb42
Forgot to add the main files!

--HG--
extra : rebase_source : a2b86131d0e3cb240b6f09a11da76244cc09b3ea
Detect music library data structures by DIDL class instead of parent id
Update music library data structure tests
Various fixes, lint and forgotten commented out lines
Removed superfluous __init__ methods in ML data structure classes
Added MLSameArtist class for use by browse function
Refactored get music lib information and added generel browse function for music library items
Added information to _music_lib doc string about how to get all search prefixes
Made ML searches return MLCategory for object.container DIDL class and MLShare only returned for share searches
Rebasing onto Master
Fixing broken test
Missing import
Merge pull request #191 from KennethNielsen/ml_from_didl_class

Ml from didl class
Merge pull request #180 from lawrenceakka/config

Initial checkin of config module
Merge pull request #192 from KennethNielsen/ml_browse

Ml browse