added new challengeEngine with provides TimelineEntries with the new HTML-format
<DA-313> Merge branch 'unstable' into DA-313
<DA-313> fix action link position
<DA-313> fix disabled action button
<DA-313> fix markup
<DA-313> fix media files border
<DA-313> fix "drallo successful" alert
<DA-313> clean up css
<DA-313> Merge branch 'unstable' into DA-313
<DA-313> fix merge
<unstable> Merge branch 'DA-313' into unstable