[telnet interface] delete & move items in playlist

The telnet interface is very useful but as far as I found out, there is no way to remove an item from the playlist. (Except than clearing it and rebuilding it).

A delete <item> command would be great.

Also, move <item> <target> to allow move right under would be nice. (I say "under" because in that way, you are able to move one at the end of the playlist, and if you want to put it first, you can still use move <item> 2)