improvements to the CMake build system

- it now can generate and install the API documentation ('make install-html')
- the information of the dune.module file is now used much more extensively
- presence of the valgrind headers is tested
- tests which cannot be run for a configuration will now appear as
  'skipped' in CDash
- adding tests does not require modifying the toplevel CMakeList.txt anymore
- introduction of the 'EwomsAddTest' cmake macro which removes quite a bit of the
  copy-and-paste from the CMakeLists.txt.
- various small loose ends have been fixed

examples/CMakeLists.txt

@@ -1,11 +1,8 @@
-# add build targets
+# set the CMake module include path
-ADD_EXECUTABLE("tutorial_decoupled" tutorial_decoupled.cc)
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/Modules")
-TARGET_LINK_LIBRARIES("tutorial_decoupled" ${EwomsLinkLibraries})
 
-ADD_EXECUTABLE("tutorial_coupled" tutorial_coupled.cc)
+# eWoms unit-testing infrastructure
-TARGET_LINK_LIBRARIES("tutorial_coupled" ${EwomsLinkLibraries})
+include(EwomsAddTest)
-
-# add required libraries and includes to the build flags 
-LINK_DIRECTORIES(${EwomsLinkDirectories})
-INCLUDE_DIRECTORIES(${EwomsIncludeDirectories})
 
+EwomsAddTest(tutorial_coupled)
+EwomsAddTest(tutorial_decoupled)