Merge branch 'np/pack'

* np/pack:
  pack-objects: fix early eviction for max depth delta objects
  pack-objects: allow for early delta deflating
  pack-objects: move compression code in a separate function
  pack-objects: clean up write_object() a bit
  pack-objects: simplify the condition associated with --all-progress
  pack-objects: remove some double negative logic
  pack-objects: small cleanup