Vis options panel

Built off of #1763 (merge that PR first)

Closes #1618 

This PR adds visualization options to allow for disabling elements (legend, tooltip) as well as custom vis options (like **mode** for histogram).

- `params` are set on a vis_type, including defaults and an editor
- The editor is used for the UI for setting the associated options
- The new renderbots (introduced in #1763) can now have their params refreshed
- 100% coverage for base and vislib `renderbot`s