SOAP support

[mike442144]

Maybe add SOAP support when posting. Body like below:

<?xml version='1.0' encoding='utf-8' ?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="http://www.example.org/baseInfo/" xmlns:ns2="http://us.xueersi.org/namespace/">
  <SOAP-ENV:Header>
    <ns2:authentication SOAP-ENV:actor="http://schemas.xmlsoap.org/soap/actor/next">
      <authinfo>...</authinfo>
    </ns2:authentication>
  </SOAP-ENV:Header>
  <SOAP-ENV:Body>
    <ns1:xxx><request>{"bbq":"0"}</request></ns1:xxx>
  </SOAP-ENV:Body>
</SOAP-ENV:Envelope>