Fix add, cycle and multiply command.

mpv.py

@@ -643,14 +643,24 @@ class MPV(object):
         """ Mapped mpv frame_back_step command, see man mpv(1). """
         self.command('frame_back_step')
 
-    def _add_property(self, name, value=None):
-        self.command('add_property', name, value)
+    def _add_property(self, name, value=1):
+        """Add the given value to the property. On overflow or
+        underflow, clamp the property to the maximum. If ``value`` is
+        omitted, assume ``1``.
+        """
+        self.command('add', name, value)
 
     def _cycle_property(self, name, direction='up'):
-        self.command('cycle_property', name, direction)
+        """Cycle the given property. ``up`` and ``down`` set the cycle
+        direction. On overflow, set the property back to the minimum, on
+        underflow set it to the maximum. If ``up`` or ``down`` is
+        omitted, assume ``up``.
+        """
+        self.command('cycle', name, direction)
 
     def _multiply_property(self, name, factor):
-        self.command('multiply_property', name, factor)
+        """Multiplies the value of a property with the numeric factor."""
+        self.command('multiply', name, factor)
 
     def screenshot(self, includes='subtitles', mode='single'):
         """ Mapped mpv screenshot command, see man mpv(1). """