Remove class loading fallback in cObject
Remove cObj->isClassAvailable() as this class was
introduced in TYPO3 4.3 before autoloading was there.
Now, with TYPO3 CMS 7, autoloading is completely done
via spl_autoload_register and class_exists() does the
autoloading automatically, both in composer-mode and
The method is therefore removed as the fallback is
pre-historic and a simple class_exists() check is added.