Also rename to sfnt2fon to better reflect usage and avoid conflicts
with the previous binary on updates.

msxml3: Use interface instead of implementation pointer to forward IEnumVARIANT::AddRef and IEnumVARIANT::Release for IXMLElementCollection.

msxml3: Add separate QueryInterface implementation for IEnumVARIANT interface exported by IXMLElementCollection.

msxml3/tests: Add a test to show that IXMLElementCollection enumerator doesn't recognize IID_IXMLElementCollection.