message: using UUID as subdirectory of additional plugins
diff: include(additionalPlugin)
  foreach(ADDITIONAL_PLUGIN_SOURCE_DIR ${EOSIO_ADDITIONAL_PLUGINS})
  - message(STATUS "[Additional Plugin] source dir: ${ADDITIONAL_PLUGIN_SOURCE_DIR}")
  - add_subdirectory(${ADDITIONAL_PLUGIN_SOURCE_DIR} ${CMAKE_BINARY_DIR}/additional_plugins/${ADDITIONAL_PLUGIN_SOURCE_DIR})
  + string(UUID PLUGIN_PATH NAMESPACE "00000000-0000-0000-0000-000000000000" NAME ${ADDITIONAL_PLUGIN_SOURCE_DIR} TYPE MD5)
  + message(STATUS "[Additional Plugin] source dir: ${ADDITIONAL_PLUGIN_SOURCE_DIR} => ${CMAKE_BINARY_DIR}/additional_plugins/${PLUGIN_PATH}")
  + add_subdirectory(${ADDITIONAL_PLUGIN_SOURCE_DIR} ${CMAKE_BINARY_DIR}/additional_plugins/${PLUGIN_PATH})
  endforeach()
  add_executable( nodeos main.cpp )
  