libsaria: Added a stop function

I stop playback, and seek to the beginning.  I do this as to different
function calls in the Libsaria class so callbacks will still trigger
(once they have been implemented).

include/libsaria/audio.h

@@ -27,6 +27,7 @@ class Audio
 		/* Control functions */
 		void play();
 		void pause();
+		void seek();
 };
 
 void audio_init(int, char **);

include/libsaria/libsaria.h

@@ -16,6 +16,8 @@ class Libsaria
 		/* Control functions */
 		void play();
 		void pause();
+		void stop();
+		void seek();
 };
 
 class Libsaria *libsaria_get();

libsaria/audio/controls.cpp

@@ -15,3 +15,16 @@ void Audio::pause()
 {
 	change_state(GST_STATE_PAUSED);
 }
+
+/*
+ * Right now I just seek to the beginning of the song.
+ * Eventually I should allow the user to seek anywhere.
+ */
+void Audio::seek()
+{
+	gst_element_seek_simple(GST_ELEMENT(player),
+				GST_FORMAT_TIME,
+				GST_SEEK_FLAG_FLUSH,
+				// Convert seconds to nano-seconds
+				0 * GST_SECOND);
+}

libsaria/controls.cpp

@@ -11,3 +11,14 @@ void Libsaria::pause()
 {
 	audio.pause();
 }
+
+void Libsaria::stop()
+{
+	pause();
+	seek();
+}
+
+void Libsaria::seek()
+{
+	audio.seek();
+}