Add 60s watchdog for nrf52

In order to restore after battery voltage sags too low

examples/companion_radio/main.cpp

@@ -223,6 +223,7 @@ void setup() {
 }
 
 void loop() {
+  board.loop();
   the_mesh.loop();
   sensors.loop();
 #ifdef DISPLAY_CLASS

examples/kiss_modem/main.cpp

@@ -119,6 +119,7 @@ void setup() {
 }
 
 void loop() {
+  board.loop();
   modem->loop();
 
   if (!modem->isActuallyTransmitting()) {

examples/simple_repeater/main.cpp

@@ -106,6 +106,8 @@ void setup() {
 }
 
 void loop() {
+  board.loop();
+
   int len = strlen(command);
   while (Serial.available() && len < sizeof(command)-1) {
     char c = Serial.read();

examples/simple_room_server/main.cpp

@@ -83,6 +83,8 @@ void setup() {
 }
 
 void loop() {
+  board.loop();
+
   int len = strlen(command);
   while (Serial.available() && len < sizeof(command)-1) {
     char c = Serial.read();

examples/simple_secure_chat/main.cpp

@@ -589,6 +589,7 @@ void setup() {
 }
 
 void loop() {
+  board.loop();
   the_mesh.loop();
   rtc_clock.tick();
 }

examples/simple_sensor/main.cpp

@@ -117,6 +117,8 @@ void setup() {
 }
 
 void loop() {
+  board.loop();
+
   int len = strlen(command);
   while (Serial.available() && len < sizeof(command)-1) {
     char c = Serial.read();