Refactoring images logo-dfg.gif to logoDFG.gif, logo-archivportal.png to
logoArchivportal.png and logo-archivportal-index.gif to
logoArchivportalIndex.gif

Changed too in apd.css line 243 referece to logo-archivportal.gif to
logoArchivportal.png. Because logo-archivportal.gif doesn't exist.