Fault Recovery and LED signals

Besides the issue with invalid opcode with virtual wuobject update, my code is working fine for self-recovery with one of my simple test applications.

In other words, when one node fails the node who detects fault will initiate recovery and all nodes that have the wuobjects or are connected to the dead node will be updated and redirected to the new node - all by itself.

Not only that, now the onboard LEDs have never being used anything like that before, every LED indicates a certain event, so it would be much easier to tell what's going on without having to attach to the node with a serial monitor.

• LED4 blinks once when it propagates a property value
• LED4 blinks twice when the propagation failed
• LED5 blinks once for sending a heartbeat message and blinks twice for finished recovering from failures
• LED6 blinks once when received a heartbeat that the node is monitoring

led.c and led.h in src folder should give enough information on how to use the onboard LEDs.

The valid version number for this working build is 3efce9f0c45d5f3e4308fe7738d7c34825e5b886