Remove manifest difference for dev branch

Simplify future merging of dev into master by removing the necessity of
changing "Deluminate-dev" to "Deluminate" in the manifest every time I
want to release. Improve the Makefile logic to build a "dev" version
including a "build number" in the version.
Workaround for filter not applied to whole window

Issue occurs when a page does not occupy the entire screen, so create a
fully transparent background element that occupies the full screen.

Fixes issue #17