Investigate colorpicking failures

[bmschmidt]

The code to identify points on mouseover seems to be breaking right now at points with especially high index numbers right now. So while mouseover works well for the first 4,000,000 or so points in a plot, lower points are not always selectable.

I suspect the problem is that the unique identifiers being generated by painting to the color canvas aren't unique enough, and that offscreen points are being identified instead. Need to check, though.

[bmschmidt]

fixed