Feature request! Add --numPlotsPerRow to plotHeatmap

[sarjopp]

Hello. I'm finding that plotHeatmap is more useful for heatmaps than the "heatmap" option in plotProfile. But plotHeatmap has one big problem: it prints ALL the heatmaps in one row! That's okay for 4 heatmaps, but I want to generate heatmaps for 10s of genes. The only workaround I see is to generate a separate matrix and a separate plotHeatmap command for every 4 genes, across over 1,000 samples.