add missing deleteTable because Erfurt_Store_Sql_Interface forced it
port contractNamespace from OntoWiki_Utils to Erfurt_Utils.php

But with a couple of modifications, because there
is, for instance, no OntoWiki::getInstance()->selectedModel
Some refactoring
moving content of Erfurt_Store->getResourceDescription to Erfurt_Rdf_Resource

+ some refactoring
Port (skyrocketing) TitleHelper from OntoWiki to Erfurt

But this time its really with skyrocketing speed!

And some test cases are on board too...
mostly Cache backends: Refactoring and corrections
Implement (still buggy) Memcached QueryCache backend