Merge branch 'np/pack'

* np/pack:
deprecate the new loose object header format
make "repack -f" imply "pack-objects --no-reuse-object"
allow for undeltified objects not to be reused

diff --cc Documentation/config.txt
Simple merge

diff --cc cache.h
Simple merge

diff --cc config.c
Simple merge

diff --cc sha1_file.c
Simple merge