GitLab

* refactor SHA1_Store

- renamed the class
- added created_on field and refactored how init is done
- wrap long lines

* wrapped longer lines

* rename json file ref_count.json

* make sha1_buf_size an argument

* update gitignore

* added tmp_dir

* added new sha1_store add and tests

* update chdir

* add debug to test

* fixing unit test for 1.8
Co-authored-by: Min Xu <min.xu.public@gmail.com>