rd3 device: scatterplot points can have point ids now.
Multiple gadget ids are concatenated via "+".
rd2plot argument for frame width, we need this to put the frame below the points in a scatterplot. The other option would be to put it there with javascript.
Fixed a bug when different colors were specified on a scatterplot. We have the same bug for other arguments, I am not sure what the generic solution is.
Add scatterplot pids to the class of the elements, it is simpler to select points this way.
rd3 device bug fixed: do not set fill and stroke for circle, polygon, polyline, rect, they are set in the style.
Gadget: highlight the same point, in a matrix of scatterplots.