* big refactor of the 'display' object. Now defined in variants/*/target modules.

variants/techo/target.cpp

@@ -12,6 +12,10 @@ VolatileRTCClock fallback_clock;
 AutoDiscoverRTCClock rtc_clock(fallback_clock);
 SensorManager sensors;
 
+#ifdef DISPLAY_CLASS
+  DISPLAY_CLASS display;
+#endif
+
 #ifndef LORA_CR
   #define LORA_CR      5
 #endif