Store MDI-related classes under gui/mdi

To better group MDI-related classes, all of them have been moved to the
´gui/mdi´ directory.

application/CMakeLists.txt

@@ -7,8 +7,9 @@ MESSAGE(STATUS "Configuring CAMPVis Application")
 FILE(GLOB CampvisApplicationSources
     *.cpp
     gui/*.cpp
-    gui/properties/*.cpp
     gui/adjusterwidgets/*.cpp
+    gui/mdi/*.cpp
+    gui/properties/*.cpp
     tools/*.cpp
 )
 
@@ -36,9 +37,9 @@ SET(CampvisApplicationToBeMocced
     gui/qtdatahandle.h
     gui/logviewerwidget.h
     gui/loghighlighter.h
-    gui/mdidockarea.h
-    gui/pipelinemdisubwindow.h
-    gui/mdifloatingwindow.h
+    gui/mdi/mdidockarea.h
+    gui/mdi/mdifloatingwindow.h
+    gui/mdi/pipelinemdisubwindow.h
     gui/adjusterwidgets/doubleadjusterwidget.h
     gui/adjusterwidgets/intadjusterwidget.h
     gui/properties/abstractpropertywidget.h

application/gui/mainwindow.h

@@ -32,7 +32,7 @@
 
 #include "sigslot/sigslot.h"
 #include "application/campvisapplication.h"
-#include "application/gui/mdidockarea.h"
+#include "application/gui/mdi/mdidockarea.h"
 #include "application/gui/pipelinetreewidget.h"
 #include "application/gui/properties/propertycollectionwidget.h"
 #include "application/gui/logviewerwidget.h"