Merge branch 'jh/add-index-entry-optim'

"git checkout" that handles a lot of paths has been optimized by
reducing the number of unnecessary checks of paths in the
has_dir_name() function.

* jh/add-index-entry-optim:
read-cache: speed up has_dir_name (part 2)
read-cache: speed up has_dir_name (part 1)
read-cache: speed up add_index_entry during checkout
p0006-read-tree-checkout: perf test to time read-tree
read-cache: add strcmp_offset function

diff --cc Makefile
Simple merge

diff --cc cache.h
Simple merge

diff --cc read-cache.c
Simple merge

diff --cc t/helper/.gitignore
Simple merge