Implement receiver HID++ connect/disconnect events

Many changes were made here but that was the biggest one.

There's currently a bug where std::system_error: Broken pipe is thrown
after launching the daemon with a receiver connector.

A workaround for this bug is to simply shake the mouse while starting
the daemon. I will investigate this soon.

src/logid/backend/dj/ReceiverMonitor.h

@@ -21,7 +21,7 @@ namespace dj
         void stop();
 
     protected:
-        virtual void addDevice(hidpp::DeviceIndex index, uint16_t pid) = 0;
+        virtual void addDevice(hidpp::DeviceConnectionEvent event) = 0;
         virtual void removeDevice(hidpp::DeviceIndex index) = 0;
 
         // Internal methods for derived class
@@ -29,8 +29,10 @@ namespace dj
         void _stopPairing();
 
         void _unpair();
+
+        std::shared_ptr<Receiver> receiver() const;
     private:
-        Receiver _reciever;
+        std::shared_ptr<Receiver> _receiver;
     };
 
 }}}