Merge branch 'rename-detection'

* rename-detection:
  RenameDetector: Only scan deletes if adds exist
  SimilarityRenameDetector: Initialize sizes to 0
  SimilarityRenameDetector: Avoid allocating source index
  SimilarityRenameDetector: Only attempt to index large files once
  SimilarityIndex: Don't overflow internal counter fields
  SimilarityIndex: Accept files larger than 8 MB
  SimilarityIndex: Correct comment explaining the logic