Add mysensors light platform

* Make light controllable independently with types V_LIGHT, V_DIMMER,
    V_RGB and V_RGBW. V_RGBW is not implemented in the frontend yet.
* Add discovery for light platform.
* Add optimistic mode config setting for switch and light
    to allow feedback state from actuator.
* Move S_LIGHT, V_LIGHT, V_STATUS types from switch to light platform.
* Change node update logging to debug from info level.
* Fix some inaccurate comments.

homeassistant/components/sensor/mysensors.py

@@ -1,5 +1,6 @@
 """
-homeassistant.components.sensor.mysensors
+homeassistant.components.sensor.mysensors.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Support for MySensors sensors.
 
@@ -30,7 +31,7 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
 
     for gateway in mysensors.GATEWAYS.values():
         # Define the S_TYPES and V_TYPES that the platform should handle as
-        # states. Map them in a defaultdict(list).
+        # states. Map them in a dict of lists.
         pres = gateway.const.Presentation
         set_req = gateway.const.SetReq
         map_sv_types = {
@@ -190,7 +191,7 @@ class MySensorsSensor(Entity):
         node = self.gateway.sensors[self.node_id]
         child = node.children[self.child_id]
         for value_type, value in child.values.items():
-            _LOGGER.info(
+            _LOGGER.debug(
                 "%s: value_type %s, value = %s", self._name, value_type, value)
             if value_type == self.gateway.const.SetReq.V_TRIPPED:
                 self._values[value_type] = STATE_ON if int(