Support doc/lit with empty soap body elements

There is some conflicting information in the different specifications regarding how to handle a method in an endpoint interface that does not take any parameters, at the moment we only support this type of method by using wrapped style.

From the BasicProfile: -

[Section 5.3.1]
....
Use of wsdl:message elements with zero parts is permitted in Document styles to permit operations that can send or receive messages with empty soap:Bodys.

From JSR-181

JSR-181 which states:

• If the operation is marked @Oneway, it MUST have a void return value, a
  single non-header parameter marked as IN, and zero or more header
  parameters.
• If the operation is not marked @Oneway, it may have one of the following
  forms:
  o A non-header parameter marked as IN, a non-header parameter marked
  as OUT, a void return value, and zero or more header parameters.
  o A single non-header parameters marked as IN_OUT, a void return
  value, and zero or more header parameters.
  o A single non-header parameter marked as IN, non-void return value
  and zero or more header parameters.

This clearly requires there to be at least one parameter for a bare doc/lit message.

From JAX-WS (Although not the current spec we implement does show how this has been clarified)

In order to qualify for use of bare mapping mode a Java method must
fulfill all of the following criteria:
1. It must have at most one in or in/out non-header parameter.
2. If it has a return type other than void it must have no in/out or
out non-header parameters.
3. If it has a return type of void it must have at most one in/out or
out non-header parameter.