Merge pull request #13 from Y-Nak/bump-version

Bump version to `0.4.1`

Merge pull request #11 from Y-Nak/bump-version

version `0.4`

Merge pull request #8 from Y-Nak/bumpup-version

0.3.0 release

0.2.1 release (#6)

0.2.0 release

Update to 0.1.1

Modify doc