fix compilation warnings

src/config-file.vala

@@ -55,10 +55,6 @@ public class ConfigFile
 
 			return this.file.save_to_file(this.filename);
 		}
-		catch(KeyFileError err)
-		{
-			return false;
-		}
 		catch(FileError err)
 		{
 			return false;

src/dbus-server.vala

@@ -5,27 +5,27 @@ public class DbusServer : Object
 		get { return pulse.muted; }
 	}
 
-	public void mute()
+	public void mute() throws GLib.Error
 	{
 		pulse.mute();
 	}
 
-	public void unmute()
+	public void unmute() throws GLib.Error
 	{
 		pulse.unmute();
 	}
 
-	public void toggle_mute()
+	public void toggle_mute() throws GLib.Error
 	{
 		pulse.toggle_mute();
 	}
 
-	public void increase_volume()
+	public void increase_volume() throws GLib.Error
 	{
 		pulse.increase_volume();
 	}
 
-	public void decrease_volume()
+	public void decrease_volume() throws GLib.Error
 	{
 		pulse.decrease_volume();
 	}

src/status-icon.vala

@@ -69,7 +69,7 @@ public class MicStatusIcon : StatusIcon
 	{
 		var about = new Gtk.AboutDialog();
 		about.set_logo_icon_name("microphone-sensitivity-high");
-		about.set_version("0.3.0");
+		about.set_version("0.3.1");
 		about.set_program_name("MicTray");
 		about.set_comments("Microphone control application");
 		about.set_copyright("Dmitry Kosenkov");