order of xml elements in wsdl

I'm suggesting to change the order of the xml elements in the wsdl generated by spyne in the following way:

it currently is
&lt;wsdl:definitions...
...
&lt;wsdl:service...
&lt;wsdl:portType...
&lt;wsdl:binding...
&lt;/wsdl:definitions&gt;

my change makes it
&lt;wsdl:definitions...
...
&lt;wsdl:portType...
&lt;wsdl:binding...
&lt;wsdl:service...
&lt;/wsdl:definitions&gt;

the motivation for the change is that although the xsd for wsdl accepts any order (so there are no actual errors with the wsdl's currently generated by spyne), some tools seem to (wrongly) be less flexible (in particular SAP webserver client)