WIP: Add Accessibility Overlay Colour
This tested commit adds a feature to Evince which makes the background of a document (pdf, ps, dvi, xps) a tolerable readable custom colour. Impaired people will love the change from either black-on-white or white-on-black. This feature is very low maintenance, and doesn't change the document - no need to save and re-open. Does not change presentation mode.
CTRL+B is the shortcut key
The custom colour can be changed with dconf: