display() nicely in IPython

[tjlaboss]

Is your feature request related to a problem? Please describe.

The IPython API provides a rich set of display() tools; see display_functions(). This allows for some very pretty printing in Jupyter notebooks used for workshops, for example.

Describe the solution you'd like

Implement _repr_html_ (or another method) for the most common user-facing objects: Cell, Surface, and Material. It would be nice to view the material components as a table, for instance.

Additional context
Add any other context or screenshots about the feature request here.

Integrating your objects with IPython

[MicahGale]

Oh also while at it: probably implement a __format__ to accept format specs.

[MicahGale]

The markdown, progress bar objects seem interesting.