Design of the "plot" command
Will be based on gnuplot, plotting the data in ascii files to eps, png or pdf images. It will consist of two parts: (i) matrix and (ii) panel. The matrix code will split the image into a set of rectangular regions. The panel code will plot the panel - 2d or 1d image. The panel code should not care (even know) in which region it is. There should be default behaviours plotting a simple stuff (e.g. plane of density) configure through cml arguments (e.g. axes and colorbar ranges). Alternatively, user can provide the gnuplot code (with several recognised variables, e.g. filename to plot) that will be used for a given panel. The code should be able to plot as panels into one image either several quantities from one data file, or a given quantity from several data files.