Merge branch 'release-v0.10.0' into develop
Fix error "uninitialized value in subtraction"
Merge pull request #26 from h-matsu/fix-subtraction-error

Fix uninitialized value in subtraction
Fix to update environment and refactoring
Fix to update Changes
Bump version to v0.10.1
Merge branch 'release-v0.10.1'