Traffic Monitor LEDs
The 4 LEDs that reflect traffic to/from the Laptop and to/from the Arduino are controlled by the Monitor class.
The Traffic class creates an instance of traffic.Monitor(). Monitor functions should only be called by the Traffic class.
When called, one of the four functions (from_LT, from_BS, to_LT and to_BS) create a thread to blink one of the LEDs.
In the traffic module