Plotting fixes

Details

Somehow, the font sizes in the plotter seem to be screwed up (again?) After some trial-and-error, I just removed a lot of clutter that I can't really make sense of what it did in the first place. Now, it seems to work. Please review!

Also, there was significant screwup with the way tags were passed around. Should be straightened out now.

A few missing options (such as control over Grid lines and titles of subplots) have been added.

New feature: multiple subplots in the same plot are now possible!