Update README

Minor comment made by IH on average gaze coordinates description

Author: royhessels

README

@@ -15,7 +15,7 @@ Quick start guide for adopting this script for your own data:
 data.time for the timestamp
 data.left.X & data.left.Y for left gaze coordinates
 data.right.X & data.right.Y for right gaze coordinates
-data.average.X & data.average.Y for average gaze coordinates
+data.average.X & data.average.Y for average of right and left gaze coordinates
 
 You may provide coordinates from both eyes, only the left, only the right, or only the average. Gaze coordinates should be in pixels, timestamps should be in milliseconds
 
@@ -24,4 +24,4 @@ You may provide coordinates from both eyes, only the left, only the right, or on
 
 Requirements: Signal Processing Toolbox for downsampling. If not available you may set opt.downsample to []. This may, however, degrade performance of the algorithm.
 
-Tested on MATLAB R2012a, R2014b & R2016a
+Tested on MATLAB R2012a, R2014b & R2016a