Added ability to store comma delimited lists of genres using lastfm
and the local genre.txt file in the usual way.

Using this, a song might now have a genre of 'House, IDM, Dance',
instead of just 'House'.
Removed some unused and commented out code.
Replaced unnecessary code with one line.
For the comma delimited lastgenre addition, the old way is default.
There is a new option called multiple_genres which defaults to False
but when set to True, the comma delimited list of genres is returned
by lastgenre.

So, if you want a comma delimited list, it is

lastgenre:
    multiple_genres: True
Removed pdb stuff and cleeaned up description.
Merge pull request #397 from rashley60/master

Added ability to store comma delimited lists of genres using lastfm