[tutorial] Adapt CMakeList.txt

* Rename coupled to implicit
* Rename decoupled to sequential

tutorial/CMakeLists.txt

 add_input_file_links()
 
-add_dumux_test(tutorial_decoupled tutorial_decoupled tutorial_decoupled.cc
-  ${CMAKE_CURRENT_BINARY_DIR}/tutorial_decoupled)
+add_dumux_test(tutorial_sequential tutorial_sequential tutorial_sequential.cc
+  ${CMAKE_CURRENT_BINARY_DIR}/tutorial_sequential)
 
-add_dumux_test(tutorial_coupled tutorial_coupled tutorial_coupled.cc
-  ${CMAKE_CURRENT_BINARY_DIR}/tutorial_coupled)
+add_dumux_test(tutorial_implicit tutorial_implicit tutorial_implicit.cc
+  ${CMAKE_CURRENT_BINARY_DIR}/tutorial_implicit)
 
 #install sources
 install(FILES
-tutorial_coupled.cc
-tutorial_decoupled.cc
-tutorialproblem_coupled.hh
-tutorialproblem_decoupled.hh
-tutorialspatialparams_coupled.hh
-tutorialspatialparams_decoupled.hh
+tutorial_implicit.cc
+tutorial_sequential.cc
+tutorialproblem_implicit.hh
+tutorialproblem_sequential.hh
+tutorialspatialparams_implicit.hh
+tutorialspatialparams_sequential.hh
 DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/tutorial)