Small implementation improvements in MCF algorithms (#180)

- Handle max() as infinite value (not only infinity()).
- Better GEQ handling in CapacityScaling.
- Skip the unnecessary saturating operations in the first phase in
CapacityScaling.
- Use vector<char> instead of vector<bool> and vector<int> if it is
possible and it proved to be usually faster.

 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()