correct centering of dots
* more options: gradient_bimodal, gradcenter, gradient_invert, controltype, fontsize.
* template for controltype=flat added.
* handling of bimodal plots in dotmode
set fonts programmatically.
remove junk
'heatmap' option for dotplot-> 'background'
objectified heatmap()
preparations for allowing multiple heatmaps on a single page
more fixes for mulitple heatmaps
mulitple heatmaps: svg/canvas placement
more support for multiple heatmaps