UP-4107:  Set focusedFragmentId only for 'favorites' type folders
UP-4107:  Rename 'focusedFragmentId' -> 'focusedFolderId' for clarity;  properly point focusedFolderId at a favorites_collection in the right circumstances
Merge pull request #327 from drewwills/UP-4107

UP-4107 : Set focusedFolderId (was focusedFragmentId) only for 'favorites_collection' type folders.