Smart Playlists

Added Smart Playlists Feature

I have the next problem:

I'm tagging songs but I want to listen and tag only the songs that have the comment field empty.
Now, you can do it!

Just create the Smart List with the comment field empty.

Introducing Smart Playlists:
Create Smart List to filter by any field you want (including extra metadata fields!)

1.6.4: Fix adjacent songs when in Smart Playlists we filter and order by any field