* Let database.Open() use schemeFromURL as well
Otherwise it will fail on MySQL DSNs.
Moved schemeFromURL into the database package. Also removed databaseSchemeFromURL
and sourceSchemeFromURL as they were just calling schemeFromURL.
Fixes https://github.com/golang-migrate/migrate/pull/265#issuecomment-522301237
* Moved url functions into internal/url
Also merged the test cases.
* Add some database tests to improve coverage
* Fix suggestions