Contiki IoT Exploration

Initializes DAG root.
In serverside we have a new reciever function that stored incoming receivers
until the max receivers to check if reached the threshold.
Then we read new readings with UDP and the compute the average of the last MAX_READINGS.

On the client side we have queue for our readings that is equal size to MAX_READINGS.
We will try to batch the inputs in the queue and based on the number of retries
we calculate the average when we are sending.
if the retry exceeds the MAX_READINGS, we replace the corresponding value
by calculating the retries % MAX_READINGS.