message: Set simulated accelerometer noise variance to zero for now
diff: #include <math.h>
  -// 3 dimensions, noise mean = 0 , noise stdev = 0.01
  -Accelerometer::Accelerometer(void) : NoisySensor(3, 0, 0.01)
  +Accelerometer::Accelerometer(void) : NoisySensor(3, 0, 0)
  {
  }
  