Telling to use a custom bootstrap file
Telling PHPUnit to look for tests under application/tests
Creating a constant for a PHPUnit runtime test environment, PHPUNIT_TEST. This will be used to hack into CI bootstrap behaviour.
Providing a $_SERVER['REMOTE_ADDR'] default value so CI's security checks won't break.
For code coverage analysis, we're filtering out CI system directory, and optionally your application/libraries directory (if you uncomment that line).