Broken visualization functions

[jan-david-fischbach]

When visualizing cells I get the following error:

The number of FixedLocator locations (3), usually from a call to set_ticks, does not match the number of ticklabels (4).

Furthermore we seem to not provide a shading parameter to pcolormesh (almost everywhere). With newer versions of matplotlib it seems to assume flat, which I don't think is what we want. We rather need nearest (e.g. for plotting the eps distribution)

[jan-david-fischbach]

MatplotlibDeprecationWarning: shading='flat' when X and Y have the same dimensions as C is deprecated since 3.3.  Either specify the corners of the quadrilaterals with X and Y, or pass shading='auto', 'nearest' or 'gouraud', or set rcParams['pcolor.shading'].  This will become an error two minor releases later.
  plt.pcolormesh(