Moving xsi type namespace processing to processAttributes method to
handle xsiTypes for object of arrays.
Allowing the property name "attributes" to be configurable.
Handle SOAP Response element value and attributes so that the attribu…
…tes of an element don't get overwritten if also a value is given.

In case a value and attributes are given, the JSON response will return an `Object` with `$value` and `attributes` (in respect to the  set `attributesKey` so that it could also be `$attributes` or something the like) instead of a `String`.