Slashes in genre-names breaks AlbumsCategoryBrowser

[01tot10]

Hello!

I use a naming convention in my beets library where I combine related genres together for a more sane browsing experience. For example, I've combined industrial and noisy stuff to 'Industrial/Experimental/Noise', and EBM and techno-y things to 'Techno/EBM/Electro'. Unfortunately, my convention seems to break what AlbumsCategoryBrowser expects as genres, and I'm not seeing any albums for those items in 'Albums By Genre' when I browse.

I looked around the source code to see if I could improve on the functionality, but I soon realized the programming is too advanced for me to keep track of how the information is flowing.. So before I go ahead and touch all the genres of my library and break the generic Albums view in terms of the chronological ordering, I was wondering if it would be easy to fix AlbumsCategoryBrowser to escape slashes so that the items would show up even with the current naming convention?

Looking forward for any insights!

[01tot10]

Created PR in #36