Experimental Scoring Behaviour

The idea is to make the backbone scoring consistent with the all atom scoring.
Before, a BackboneList had to be provided for each scoring action. There were
therefore two types of interactions: interactions towards the scoring environment
and interactions within the BackboneList. Now, the BackboneList is set to the
scoring environment before scoring. There are now ONLY interactions towards the
environment. What remains is: profiling / documentation update

Advantages:
 - If you want to score several loops at once, you have less mess to sort out
   which interactions are towards the environment and which ones are within
   the different loops. (And that was the main goal)
 - Consistent interface between backbone scoring, all atom scoring and
   SidechainReconstructor
 - Less code duplication. The env listeners do some precalculations. These
   precalculations had to be done for the actual loops as well.