add tox.ini
add .python-version
add setup.py
add git_ls_date
add test.
change .python-version
add testfile1 for testing.
add testfile2 for testing.
add testfile3 for testing.
add testfile4 for testing.
change testfile1 for testing.
GitCommandErrorException include git command. and fix test.
fixes git command functionn and Commit class.
add FilesParser
add test for FilesParser
change testfiles for testing.
fix Commit.__str__() format
change testfile1 for testing.
deps mock for testing.
separate function in FilesParser.