Security personalizer rewritten (#794)

* Removed ability to lock data section
* Introduced "guided mode" to simplify process
* Refactored the sketch to be less monolithic
* Print details and instructions in tables
* Use device unique ID as serial when
* Calculate and store personalization checksum
* Print serial in a copy+paste friendly manner (fixes #804)
* Clarify meaning of UART confirmation (fixes #805)

core/MySensorsCore.cpp

@@ -118,6 +118,7 @@ void _begin(void)
 	ledsInit();
 #endif
 
+	(void)signerValidatePersonalization();
 	signerInit();
 
 	// Read latest received controller configuration from EEPROM