The HostingServiceClient client class as largely undocumented: it

contained no argument or return type docs. This has been corrected.

Several of its methods also had mutable defaults, which has been

replaced with None so that the values do not persist to other calls.

The _build_form_data method has been made public and static, since it

should never have to access instance variables to do the serialization

of the provided data and is a generally useful method outside the class.

Ran unit tests.
Built the docs and read through them.