Support CUE and other playlists from filesystem tree

I've tested it with 
mpd --version
mpd (MPD: Music Player Daemon) 0.18~git 

Copyright (C) 2003-2007 Warren Dukes <warren.dukes@gmail.com>
Copyright (C) 2008-2012 Max Kellermann <max@duempel.org>
This is free software; see the source for copying conditions.  There is NO
warranty; not even MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Decoders plugins:
 [mad] mp3 mp2
 [vorbis] ogg oga
 [oggflac] ogg oga
 [flac] flac
 [audiofile] wav au aiff aif
 [dsdiff] dff
 [dsf] dsf
 [ffmpeg] 16sv 3g2 3gp 4xm 8svx aa3 aac ac3 afc aif aifc aiff al alaw amr anim apc ape asf atrac au aud avi avm2 avs bap bfi c93 cak cin cmv cpk daud dct divx dts dv dvd dxa eac3 film flac flc fli fll flx flv g726 gsm gxf iss m1v m2v m2t m2ts m4a m4b m4v mad mj2 mjpeg mjpg mka mkv mlp mm mmf mov mp+ mp1 mp2 mp3 mp4 mpc mpeg mpg mpga mpp mpu mve mvi mxf nc nsv nut nuv oga ogm ogv ogx oma ogg omg psp pva qcp qt r3d ra ram rl2 rm rmvb roq rpl rvc shn smk snd sol son spx str swf tgi tgq tgv thp ts tsp tta xa xvid uv uv2 vb vid vob voc vp6 vmd wav webm wma wmv wsaud wsvga wv wve
 [pcm]

Output plugins:
 null fifo alsa ao httpd

Encoder plugins:
 null vorbis wave flac

Input plugins:
 file curl ffmpeg mms

Playlist plugins:
 extm3u m3u xspf pls asx rss cue cue

Protocols:
 file:// http:// mms:// mmsh:// mmst:// mmsu:// gopher:// rtp:// rtsp:// rtmp:// rtmpt:// rtmps://