What's the problem this feature will solve?

I am currently working on a project using mesa. Great framework! The problem is that I use ContinuousSpace, and want to visualise it. Is this something you are working on?

Steps to reproduce:

• Open Wolf Sheep Predation
• Open the plot and note that "wolves" is a line plot
• Run set-current-plot-pen "wolves"
• Run set-plot-pen-mode 1 ; bar mode
• Open the plot again and check the mode of "wolves"; it will still say "Line"
• As a sanity check, feel free to plot as many points as you want with these settings, while noting that the mode stays "L

In our example files, we use [link](@ref) to refer to the API.

Something that would be helpful to the documentation (and great for a fist issue to a new contributor!), would be links that track back from the API documentation to specific places in the examples where that function is used.

As an example, the current docstring for kill_agent!:

"""
      kill_agent!(agent::Abst

The attr ranges could accept an interval of chars (according to ASCII). The attr ranges are mainly used by the plugins to define their attributes, e.g., see the attributes of this plugin.

The examples below could be

Investigate how to build a .deb installer.