mucke-backend: Results can now be sorted in descending order as a core feature. This makes it very easy to re-sort after modifying scores.
mucke-ui: The credibility feature (tickbox) works not as results are being re-scored based on the credibility of the users and sorted in descending order.

TODO:
1) Normalize lucene scores so that they are all between 0.0 and 1.0. This avoids that the credibility re-scoring gets less impact for values running over a score of 1.0.
2) NICE TO HAVE: Add a sliderbar to allow users of the demo to leverage the impact of the credibility score
3) NICE TO HAVE: List the users of the given result set and their credibility so that uses can better understand the results and their ranking.
4) NICE TO HAVE: List not only images and captions, but also score and userid to help people understand the results and their ranking.