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})

 ADD_LIBRARY(lemon

   arg_parser.cc

   base.cc

   color.cc

   random.cc)

 INSTALL(

   TARGETS lemon

   ARCHIVE DESTINATION lib

   COMPONENT library)

 INSTALL(

   DIRECTORY . bits concepts

   DESTINATION include/lemon

   COMPONENT headers

   FILES_MATCHING PATTERN "*.h")