[Chicago] Bokeh methods as arguments

[Robin Fishbein]

Thanks Brian, Aaron, Phil!
I tested these approaches, and each one of them worked. I imagine I'll probably use Brian's approach, defining a function, because it decouples the list of shape method names from the Figure instance's symbol.

I had tried creating my own class based on Figure, but Jupyter Notebook didn't want to display an object not specifically of the Figure class. I also got errors when trying to use add my own method to a Figure instance with setattr.

Bokeh's scatter marker methods where the marker has no interior (x, asterisk, and one other I can't think of) conveniently ignore fill_* keyword arguments. Probably didn't have my use case in mind, rather just if someone decides to change from 'circle' to 'x' they can do so without having to know to remove the fill_color.

-Robin