playlist: implement type-ahead search in the playlist
playlist: implement type-ahead search in the playlist

Implement a basic form of type-ahead search for the playlist treeview
widget. This makes it easy to jump to an item in the playlist by name
if the title or filename is known.

https://bugzilla.gnome.org/show_bug.cgi?id=599795

mediaserver2-plugins/totem-mediaserver2,mediaserver2-plugins/totem-mediaserver2