Plotting functionality in the global fit to include all plots even if there are many of them

[GuiMacielPereira]

Problem
The way that I coded the script for global fit (i.e. fit with shared parameters over workspace groups) has a threshold for the number of subplots in the figure it outputs. I made it so that any figure with more than 16 plots (i.e. more than 16 groups) does not get plotted.

Solution
Experiment with matplotlib to create a plot in mantid that is able to show all subplots.