libsaria: Chose next songs from the queue

If there are songs in the queue, I pick from there.  Otherwise, I pick
from the library.

include/libsaria/queue.h

@@ -14,6 +14,8 @@ namespace libsaria
 		void for_each(SourceModel *);
 		unsigned int size();
 
+		void next();
+
 	}
 }
 

libsaria/controls.cpp

@@ -1,13 +1,17 @@
 
 #include <libsaria/controls.h>
 #include <libsaria/library.h>
+#include <libsaria/queue.h>
 
 namespace libsaria
 {
 
 	void next()
 	{
-		library::next();
+		if (queue::size() > 0)
+			queue::next();
+		else
+			library::next();
 	}
 
 }; /* Namespace: libsaria */

libsaria/queue/queue.cpp

@@ -35,4 +35,11 @@ namespace libsaria
 		return playqueue.size();
 	}
 
+	void queue::next()
+	{
+		library::play_id(playqueue.front());
+		playqueue.pop_front();
+		trigger_callback(QUEUE_REFRESH);
+	}
+
 } /* Namespace: libsaria */