Add ability to change the volume (#162)

mirobo sound shows current settings
mirobo sound <volume> changes volume, where volume is 0-100
passing --test will give a test voice from the vacuum for testing sound levels

Fixes #159

miio/vacuum.py

@@ -235,8 +235,12 @@ def sound_volume(self) -> int:
         return self.send("get_sound_volume")[0]
 
     def set_sound_volume(self, vol: int):
-        """Set sound volume."""
-        raise NotImplementedError("unknown command&parameters")
+        """Set sound volume [0-100]."""
+        return self.send("change_sound_volume", [vol])
+
+    def test_sound_volume(self):
+        """Test current sound volume."""
+        return self.send("test_sound_volume")
 
     def serial_number(self):
         """Get serial number."""

miio/vacuum_cli.py

@@ -421,9 +421,16 @@ def cleaning_history(vac: miio.Vacuum):
 
 
 @cli.command()
-@pass_dev
-def sound(vac: miio.Vacuum):
-    """Query sound settings."""
+@click.argument('volume', type=int, required=False)
+@click.option('--test', 'test_mode', is_flag=True, help="play a test tune")
+@pass_dev
+def sound(vac: miio.Vacuum, volume: int, test_mode: bool):
+    """Query and change sound settings."""
+    if volume is not None:
+        click.echo("Setting sound volume to %s" % volume)
+        vac.set_sound_volume(volume)
+    if test_mode:
+        vac.test_sound_volume()
     click.echo("Current sound: %s" % vac.sound_info())
     click.echo("Current volume: %s" % vac.sound_volume())
     click.echo("Install progress: %s" % vac.sound_install_progress())