Fixes problems on small nodes mapping and on GnuPlot graphical output.
Fixes problems on small nodes mapping and on GnuPlot graphical output.

Partially includes code written by Raffaella Rizzi (@rrizzi).

AlgoLab/RNA-seq-Graph,AlgoLab/RNA-seq-Graph,AlgoLab/RNA-seq-Graph,AlgoLab/RNA-seq-Graph