Whitelist all files in includes for code coverage reports

Use PHPUnit's white listing feature[1] to load all files in includes for the code coverage report. If necessary skip files that can't be included without causing errors (e.g. because they depend on variables like $phpbb_root_path to be set).

[1] http://www.phpunit.de/manual/3.2/en/appendixes.configuration.html#appendixes.configuration.blacklist-whitelist