[co2] Remove implicit folder layer

dumux/porousmediumflow/co2/CMakeLists.txt

-add_subdirectory("implicit")
+
+#install headers
+install(FILES
+model.hh
+volumevariables.hh
+DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/porousmediumflow/co2)

dumux/porousmediumflow/co2/implicit/CMakeLists.txt

-
-#install headers
-install(FILES
-model.hh
-volumevariables.hh
-DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/porousmediumflow/co2/implicit)

test/porousmediumflow/co2/implicit/heterogeneousproblem.hh

@@ -28,7 +28,7 @@
 #include <dumux/discretization/box/properties.hh>
 
 #include <dumux/porousmediumflow/problem.hh>
-#include <dumux/porousmediumflow/co2/implicit/model.hh>
+#include <dumux/porousmediumflow/co2/model.hh>
 
 #include <dumux/material/fluidsystems/brineco2.hh>
 #include <dumux/discretization/box/scvftoscvboundarytypes.hh>

test/porousmediumflow/co2/implicit/heterogeneousspatialparameters.hh

@@ -31,7 +31,7 @@
 #include <dumux/material/fluidmatrixinteractions/2p/regularizedbrookscorey.hh>
 #include <dumux/material/fluidmatrixinteractions/2p/efftoabslaw.hh>
 
-#include <dumux/porousmediumflow/co2/implicit/model.hh>
+#include <dumux/porousmediumflow/co2/model.hh>
 
 namespace Dumux
 {