Adding REGEXP and SOUNDS LIKE operators to MySql adapter.

- Adding unit test.
- Adding mysql adapter mock for unit tests.
Merge pull request #1116 from davidpersson/feature/mysql-operators

Adding REGEXP and SOUNDS LIKE operators to MySql adapter.
Documenting links to initialized properties.
Specifying exact types instead of mixed in docblock.
Expanding and formatting docblocks of `Unit`.

- Rearranging and grouping methods.
Fix casing of type class.
Refactoring test runner error handler.