ocarina: Move songlist.h

It really should go into the include directory.  I don't want to use
relative paths to include header files in a subdirectory... I don't know
why I even did it in the first place!

ocarina/library.cpp

@@ -2,7 +2,7 @@
 #include <ocarina/library.h>
 #include <ocarina/body.h>
 #include <ocarina/gtk.h>
-#include "songlist/songlist.h"
+#include <ocarina/songlist.h>
 
 #include <libsaria/library.h>
 #include <libsaria/track.h>

ocarina/songlist/songlist.cpp

@@ -3,11 +3,10 @@
 using namespace std;
 
 #include <ocarina/gtk.h>
+#include <ocarina/songlist.h>
 #include <libsaria/library.h>
 #include <libsaria/print.h>
 
-#include "songlist.h"
-
 SongList::SongList()
 {
 }