fix MySQL collations

[jrwdunham]

The Unique constraint is not working because of the collation utf8_general_ci. Thus a tag like "Accusative" will cause a 500 db error if "accusative" is already present, even though the OLD's validation will let it pass. This messes up x-2-OLD migration scripts in particular.

The current "fix" is to alter the collation of a specific column as needed. ALTER TABLE tag MODIFY name VARCHAR(255) COLLATE utf8_bin;

Changing everything to utf8_bin may have unintended consequences, related to:

• case-sensitive search
• performance