adding another nested interpolation-strategy and fixing the index-rebuilding in BAMPredicateReducer. Seems to work better: correct results (instead of timeouts) on simple fibo-files.

git-svn-id: https://svn.sosy-lab.org/software/cpachecker/branches/bamRecursion@13741 4712c6d2-40bb-43ae-aa4b-fec3f1bdfe4c