remove unused method
Instruct MySQL users to set DATABASE_ENCODING to `utf8mb4`.

cf. GH-286
Merge pull request #487 from cantino/minor_admin_cleanup

remove unused method
update CHANGES.md
fix _response_ description
Merge pull request #491 from cantino/maintain_changes

update CHANGES.md
Merge branch 'master' into table_sorting
integrate knu's suggestions