wsdl2py: fix call parameters in generated Django example code
py2wsdl: fix bad type references in generated WSDL

We must know the referenced types for ListElement in order to
generate a valid schema. The error occured when using the
built-in WSDL generation (see soapbox issue #18) but I was
unable to reproduce the error condition in a test case so this
change comes without a test case.
add py2xsd bugfix/improvement to changelog