Greatly extend and improve the test file for adaptors (#67)

- Add concept checks for the alterable, extendable, erasable
and clearable adaptors.
- Add test cases for modifying the underlying graphs through adaptors
whenever it is possible.
- Check the conversions between Node, Arc and Edge types.
- Add more test cases for the adaptor-specific functions and maps:
enable(), disable(), status(), forward(), backward(), CombinedArcMap,
CombinedNodeMap, ResidualCapacity etc.
- Use checkGraphIncEdgeArcLists() to simplify the test cases for
undirected graphs.
- Add test cases that use static graph structure (GridGraph) with
several adaptors combined.
- Add comments for the test cases.

INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR})

LINK_DIRECTORIES(${CMAKE_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(DEMO_NAME)