input:   raw Vicon marker and eye data

     output:  behavior data including
     
              1) horizontal head position
              2) head height
              3) translational speed
              4) azimuth head direction corrected for tilt
              5) azimuth movement direction
              6) head tilt: yaw, pitch, roll
              7) head angular velocity about: yaw, pitch, roll
              8) 3D heading vector and arena intersection
              9) egocentric boundary
              10) eye-in-head position
              11) azimuth gaze direction
              12) gaze vector and arena intersection