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(TESTS

  bfs_test

  circulation_test

  counter_test

  dfs_test

  digraph_test

  dijkstra_test

  dim_test

  error_test

  graph_adaptor_test

  graph_copy_test

  graph_test

  graph_utils_test

  hao_orlin_test

  heap_test

  kruskal_test

  maps_test

  max_matching_test

  radix_sort_test

  path_test

  preflow_test

  random_test

  suurballe_test

  time_measure_test

  unionfind_test)

FOREACH(TEST_NAME ${TESTS})

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

  TARGET_LINK_LIBRARIES(${TEST_NAME} lemon)

  ADD_TEST(${TEST_NAME} ${TEST_NAME})

ENDFOREACH(TEST_NAME)