Complete EtherNet/IP encapsulation parsing
o Removed unnecessary state_input 'cycle' storage in data artifact
o Repositioned default state_input collection to '<context>.input'
  instaed of <context>_input, so that data artifact is automatically
  tidied up, when raw input is converted to target data type (eg. by
  state_struct)
o Corrected enip_header parser to collect .status element
o Added enip_machine which parses EtherNet/IP header and encap. data
o Advanced cpppo.__version__ to 0.1
Support reconstruction of EtherNet/IP packets from data artifact