Guide on how to adapt the look and feel of the engage components and the admin UI

Many adopters would like to adapt the look and feel of matterhorn. This can be done in a limited way with chaning the CSS files and replacing some graphics. The modules have to be rebuild etc.

The current documentation for this is very minimal and outdated as the ThemeRoller is not working anymore

This should be documented in the release docs for 1.4/trunk as the player has changes in every release:
https://opencast.jira.com/wiki/display/mh14/Engage