bug 1049258 - Make it easier to get frame uniformity graphs

Updated with your previous feedback. We store frame position data as { layerID: [ [x0, y0], [x1, y1] ] } then convert it to the appropriate format for the chart API. Also updated to display a text message on how to get the frame position data. I also filter out layers that are [0,0] since it spammed the graph and made the front end really slow.