allow types with no attributes to be deleted
remove delete TypeSystem from test
Merge branch 'master' into delete_types_without_attrs
Merge branch 'master' into delete_types_without_attrs
changelog and version bump
Merge branch 'delete_types_without_attrs' of github.com:onefinestay/kaiso into delete_types_without_attrs
Merge pull request #90 from onefinestay/delete_types_without_attrs

Allow types with no attributes to be deleted