rename draw() as plot()

[dankelley]

I've figured out the magic incantations that let me specialize the plot() generic in an S7 system, so I plan to go ahead and remove the temporary draw() name. I want to use the standard generic names for discoverability.

I think I have a print method too, and, if so, then I'll handle that as well. I'll do this in a new branch and merge back into "develop" when it all works.

I'll bump the version number (which still starts with 0.1, so I think it's ok to be doing this sort of renaming).

[dankelley]

I did this but forgot to close the issue