- moved to new EasyBPEL/EasyViper API:
  - InternalMessage -> Message
  - ExternalMessage -> Message
  - BPELInternalMessage -> Message
  - BPELInternalMessageImpl -> MessageImpl
  - no more DefaultBPELMessageConverter
- moved the type of valueElmt from xsd:int to xsd:double into factorial.wsdl
  This is implied by the new XPATH engine used by EasyBPEL.
  With the previous XPATH engine used, anIntegerVariable - 1 produced anIntegerValue
  With the new XPATH engine used,      anIntegerVariable - 1 produces aDoubleValue
  So the factorial BPEL process produces now a double result when it produced an integer result previously.
  
WIP: some issues are still to be resolved for running all FraSCAti's BPEL-based examples (crisis, nrbc, picweb)