Feature: Change html renderer to auto-zoom-to-fit on initial load.

[nathan-at-least]

If the html renderer could zoom-to-fit when first loaded, it would be much more convenient. Then users zoom into areas of interest.

I currently always open the html view, then zoom out + scroll to see the whole thing, then zoom in, so if we can just automate that first part it would be nice (and less confusing).

This would address #38 .