update version info (#362)

Merge pull request #335 from lmntal/update-version-info

update version info

Merge pull request #308 from lmntal/version_2_6_0

Version update(2.6.0)

Merge pull request #262 from lmntal/develop

Version 2.5.0

Merge pull request #210 from lmntal/develop

Version 2.4.0

Merge pull request #68 from lmntal/develop

2.3.1 release

Merge pull request #51 from lmntal/develop

Release v2.3.0