Also unhide tracks for crates and playlists.
Merge pull request #261 from ywwg/autodj-showall

Auto DJ should show tracks that have been hidden in the library.
Merge branch 'master' into DJO-hacks-trunk
Also unhide tracks if added via Libary right-click menu.
Merge branch 'master' into DJO-hacks-trunk
set value after range, this way it is verified with the new range.
Merge branch 'master' into DJO-hacks-trunk