Ugly hack to fix two strict standarts errors:
* Declaration of Image::newFromTitle() should be compatible with that of LocalFile::newFromTitle() : Moved Image class to Image.php, will only be loaded when an old extension need it.
* Declaration of OldLocalFile::newFromTitle() should be compatible with that of LocalFile::newFromTitle() : Added an unsed param to LocalFile::newFromTitle() with a null default value, also added the null default value to OldLocalFile::newFromTitle() but that function will throw an Exception if that value isn't modified (even if these functions should not be called by extensions).
Pass $suffix parameter to File::getArchiveRel() in File::getArchivePath()