Merge branch 'jc/fix-tree-walk' into pu

Merge branch 'jc/fix-tree-walk' into pu

* jc/fix-tree-walk:
  read-tree --debug-unpack
  unpack-trees.c: look ahead in the index
  unpack-trees.c: prepare for looking ahead in the index
  traverse_trees(): handle D/F conflict case sanely
  more D/F conflict tests
  tests: move convenience regexp to match object names to test-lib.sh
  unpack_callback(): use unpack_failed() consistently
  unpack-trees: typofix
  diff-lib.c: fix misleading comments on oneway_diff()