* Add test for precise timestamps schema building
* Create precise timestamp columns on MySQL 5.6+
* Increase precision of timestamps to microsecond
- Six is the maximum that it supports and there's no reason not to use
the maximum available precision.
* Add warning when version is not specified in MySQL
* Update warning message when missing mysql version
* Fixing issue with add columns on tables failing if using both after and collate
* Adding tests for collate modifier alongside first and after modifiers
* fixed table alter attribute order. (first, after)
* add test cases, alter table position with comment.
* add real database test cases.
* after, first tests only mysql or mariadb.
Only left alone ones in `test/tape/transactions.js` which would just
cause unnecessary conflicts and get cleaned up by separate pull
request #1257 anyway.
