[UPDATE] missing SoapClient options, SoapClient overriding

Missing SoapClient options have been added.

Now we can override easily the SoapClient class that is used by the
WsdlClass. Refer to the new method WsdlClass::getSoapClientClassName()
to learn how it works. Basically, the overridding class must override
the native PHP SoapClien class and it must be named as:
{PackageName}SoapClient.