ability to specify details for SOAP faults

[FelixSchwarz]

soapfish does not support additional details in soapfaults. Martin Mrose added support for that in f1559ca but that implementation is too hacky. Also the current code is much better suited for that because a service can already return a SOAPError which should be extended to include detail information.

Steps for implementation:

• extend SOAP 1.1 Fault class (soapfish.soap11.Fault) with detail argument
• extend SOAP 1.2 Fault class (soapfish.soap12.Fault) with detail argument
• extend SOAPError with detail attribute
• render detail tag in SOAPDispatcher
• SOAP.parse_fault_message() should handle additional details
• client stub should return fault details

additional information:

• SOAP 1.1 spec
• SOAP 1.2 spec
• MSDN: section "Fault/detail"