Create implementation of proximity sensor code.

The fancy rockwell proximity sensor will be used to detect wether or not the elevator is in the "down" position. It is capable of detecting at ranges as short as an inch, so we can collaborate with design and mech to put in the right place.

1. The sensor puts a analog voltage out on a certain pin that indicates the range it is sensing.
2. Research how to write robot.py code to read an analog voltage values. Make sure that the range of voltages output by the sensor is in the range that can be read by RoboRio. If it isn't, we'll need to ask electrical to provide us with a voltage divider of some kind (to scale it down...)

If you don't get any code written, at least publish the results of your research in the comments for this issue.