Merge branch 'lt/in-core-index'

* lt/in-core-index: lazy index hashing Create pathname-based hash-table lookup into index read-cache.c: introduce is_racy_timestamp() helper read-cache.c: fix a couple more CE_REMOVE conversion Also use unpack_trees() in do_diff_cache() Make run_diff_index() use unpack_trees(), not read_tree() Avoid running lstat(2) on the same cache entry. index: be careful when handling long names Make on-disk index representation separate from in-core one