Rename min mean cycle classes and their members (#179)
with respect to the possible introduction of min ratio
cycle algorithms in the future.

The renamed classes:
- Karp --> KarpMmc
- HartmannOrlin --> HartmannOrlinMmc
- Howard --> HowardMmc

The renamed members:
- cycleLength() --> cycleCost()
- cycleArcNum() --> cycleSize()
- findMinMean() --> findCycleMean()
- Value --> Cost
- LargeValue --> LargeCost
- SetLargeValue --> SetLargeCost

INCLUDE_DIRECTORIES(

  ${PROJECT_SOURCE_DIR}

  ${PROJECT_BINARY_DIR}

)

LINK_DIRECTORIES(

  ${PROJECT_BINARY_DIR}/lemon

)

SET(DEMOS

  arg_parser_demo

  graph_to_eps_demo

  lgf_demo

)

FOREACH(DEMO_NAME ${DEMOS})

  ADD_EXECUTABLE(${DEMO_NAME} ${DEMO_NAME}.cc)

  TARGET_LINK_LIBRARIES(${DEMO_NAME} lemon)

ENDFOREACH()