Allow multiple sensor data to be read from Arduino

[ridhitbhura]

https://github.com/cornellhyperloop/electrical/blob/master/State_Estimation/src/statemachine.cpp

[agh93]

Have 3 sensors being read currently: thermistor, ultrasonic rangefinder, and inductive proximity sensor.

Data is being sent as:

• Thermistor: T,value
• Ultrasonic Rangefinder: U,value
• Inductive Proximity Sensor: I,value

Example data read into C: T,86.94 U,1.88 I,0 T,87.01 U,0.33 I,1

New code is located in: Sensors/InductProx_Ultrasonic/InductProx_Ultrasonic.ino