Refactor alarm code

- Fixes Alarms bypassing TX restrictions

- Adds enumerations

- Makes use of mode ALARM_STATE_SITE_ALARM (formely ALARM_STATE_ALARM) instead
  checking against ALARM_STATE_TXALARM && ALARM_MODE == ALARM_MODE_TONE
  all over the place

radio.h

@@ -50,7 +50,8 @@ enum VfoState_t
 	VFO_STATE_TX_DISABLE,
 	VFO_STATE_TIMEOUT,
 	VFO_STATE_ALARM,
-	VFO_STATE_VOLTAGE_HIGH
+	VFO_STATE_VOLTAGE_HIGH,
+	_VFO_STATE_LAST_ELEMENT
 };
 typedef enum VfoState_t VfoState_t;