Refs #4739, make sure recursive directory links are created even when --persist-fixture-data is used.

Refs #4739, #4189, remove persist_fixture_data config option code, placed OmniFixture into a namespace, removed PHP screenshot testcase classes and added fixture for use w/ JavaScript screenshot tests.

Trying to re-enable these tests now that we've rewritten how archive.php works, maybe this will work better?

- Modify test user adding logic to hash password instead of using pre-hashed password.
- Allow testing environment to be configured via Option values that start w/ 'Tests.'.
- Put a couple test classes into namespaces. Add test event to Piwik\Mail class so emails can be intercepted.
- Change some test logging level to INFO.
- Added load + reload methods to PageFacade in capture.js

Add unit test check PHP files start with <?php -> prevent human error when IDE does not show white spaces