Change font size in OMEdit plot windows

[Francesco Casella]

Currently, OMEdit plot windows use a fixed size font for the numbers on the axes and for the legend of the variables. The overall appearence is fine for medium-resolution screens, e.g. 1200x800. When switching to higher resolution screens, these numbers tend to be comparatively small, so if one wants to use a screenshot directly, e.g. by copy-and-past in a report, they typically end up being unreadable because they are too small.

@adeas31, could you add the possibility of changing the base font for axes and legends? That would be very helpful if one wants to get a decent result without using external scripts (Pyton, Matlab) to generate professionally-looking vector images.

[Adeel Asghar]

Done in fa0a161/OpenModelica.