show notification on mute/unmute. fix travis

.travis.yml

@@ -13,11 +13,12 @@ addons:
             - libgee-0.8-dev
             - libpulse-dev
             - libgtk-3-dev
+            - libnotify-dev
             - ninja-build
             - meson
 
 script:
     - mkdir builddir
     - meson ./ ./builddir
     - ninja -C builddir
-    - ninja -C builddir test
+    - ninja -C builddir test

src/mictray.vala

@@ -30,7 +30,7 @@ class MicTrayApp : Gtk.Application
 		{
 			status_icon.update();
 
-			if (config.show_notifications && pulse.old_volume != pulse.volume)
+			if (config.show_notifications && pulse.old_volume != pulse.volume || pulse.old_muted != pulse.muted)
 			{
 				try
 				{

src/pulse.vala

@@ -9,6 +9,7 @@ public class Pulse : Object
 	public int volume;
 	public int old_volume;
 	public bool muted;
+	public bool old_muted;
 
 	public Callback change_callback;
 	public Callback source_change_callback;
@@ -184,6 +185,7 @@ public class Pulse : Object
 
 			this.old_volume = this.volume;
 			this.volume = (int)((info.volume.avg() / (float)PulseAudio.Volume.NORM) * 100);
+			this.old_muted = this.muted;
 			this.muted = (bool)info.mute;
 
 			this.change_callback();