Release v0.4.0.

Trying to fix deps.

Fixed undefined constants. These were not added to available config b…

…ecause they are used for DOMPDF web interface, which is not supported by DOMPDFModule.

Merge pull request raykolbe#7 from jamiehannaford/patch-1

Added an example to help out users to set variables

Incrementing release

* Tagged for release.