Provide support for nillable types in a WSDL file.
Provide support for nillable types in a WSDL file.

git-svn-id: abaeb2b3ba5a94ed391a9405ad7d63d0414021c9@22560 44c647ce-9c0f-0410-b52a-842ac1e357ba

MadCat34/zend-soap,Maks3w/zend-soap,oswaldderiemaecker/zend-soap,Tiger66639/zend-soap