Data view for Histogram1d

[frauzufall]

It would be great have a data view for Histogram1d objects in order to do something like this:

Histogram1d<FloatType> histogram = ij.op().image().histogram(img);
ij.ui().show(histogram);

Currently this crashes with java.lang.ArrayIndexOutOfBoundsException: 1 at this line because the DefaultDatasetView cannot handle 1D.

[ctrueden]

I just ran into this again.

More generally, we should support display of 1D images (by converting them to a 2D with length 1 in Y). And if it's a Histogram1d specifically, use the PlotService in whatever form it ends up, once that is complete and merged.