Imu Controller Spike

This is really just meant to be a spike to try some things out for the IMU/Accelerometer with separated controllers. I haven't extended it to Temperature or Gyro because I wanted to get some feedback first.

There is a controllers service which is responsible for mapping controllers on boards. There are two controllers implemented in this pass: AnalogAccelerometer and MPU6050. Thy both expose data.accelerometer[x,y,z] data points, but they get the data in different ways.

I tested this with an analog Accelerometer as well as with the MPU-6050.
@rwaldron said:
> magic numbers need to be accompanied by comments that explain and, whenever possible, links to references

Agreed.  Need to reference [this](http://playground.arduino.cc/Main/MPU-6050#short)