presence: Add sensor to redundancy policy api

Include a reference to the sensor changing state when sensor
implementations ping the policy object.

This allows policy logic based on multiple sensors, simultaneously.

Change-Id: I44cf00c7ecd220d0cc99e51ca6093bac6da7343c
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/presence/rpolicy.hpp b/presence/rpolicy.hpp
index 34beb77..8f7db3e 100644
--- a/presence/rpolicy.hpp
+++ b/presence/rpolicy.hpp
@@ -9,6 +9,8 @@
 namespace presence
 {
 
+class PresenceSensor;
+
 /**
  * @class RedundancyPolicy
  * @brief Redundancy policy interface.
@@ -44,8 +46,9 @@
          * the inventory and execute their policy logic.
          *
          * @param[in] present - The new state of the sensor.
+         * @param[in] sensor - The sensor that changed state.
          */
-        virtual void stateChanged(bool present) = 0;
+        virtual void stateChanged(bool present, PresenceSensor& sensor) = 0;
 
         /**
          * @brief monitor