Track number of ignored aliases
Only accept the largest jitable region
Fix use of wrong iterator in ScopMapper

* This mainly fixes the use of the NonAffineScopDetection::iterator
  inside ScopMapper. We actually do not want to iterate over the
  required parameters map, because there could be parameters of
  rejected Scops in there. This can happen, if the Scop gets
  rejected after we passed a few jitable non-affine expressions.

* The rest of the patch unfortunately contains a lot of changes in
  debug output (...and I was too lazy to split it all up, sorry).