Dotplot should be able to generate a heatmap

[magickris93]

We should add an option to present result as a heatmap. I think it could be a good idea to use matplotlib's pyplot package. Examples would be https://plot.ly/matplotlib/heatmaps/ and http://heartland.geocities.jp/ecodata222/ed-e/ede1-3-0.html.

[krassowski]

Did you think about a result similar to:

./dotplot.py --fasta 1.fa 2.fa --gui --window_size 2

(branch: plotter)?