Format background, text for 'Feature Info' widget

[wayfaringrob]

Currently the Feature Info widget only supports a white background. You can only set text size and color; seems to be bold Avenir whether you like it or not. I would like to be able to customize the background and format the default (no data) text like other widgets.

Also, even if you leave 'Respect source' checked, it removes things like URL underlines.