Reduce include dependences in GUI; break cyclic dependence between View and Model

• renamed directories from plural to singular (Views->View, Utils->Util, etc etc)
• made GUI/Model independent of GUI/View
• organized GUI/Model into subdirectories
• moved GUI/main to App
• moved files from GUI/View to GUI/View/Toplevel
• broke most cyclic dependences between subdirectories of GUI/View (the remaining ones are mostly for calling functions from ProjectManager that should be moved down to ProjectDocument)
• obtained two subdirectories of GUI/Model with non-cyclic dependences (Component, IO); all other subdirectories still forming a big interdependent cluster
• removed some unused source files
• removed numerous unneeded includes
• corrected a few relative include paths
• splitted several source pairs into two pairs
• splitted class Application into two (ApplicationSettings vs SessionData)
• renamed many namespaces
• shuffled code in several functions to treat anomalous conditions first; no else after return
• substituted QWidget::parentWidget for m_mainWindow and other self-made solutions
• converted SavePlotAssistant from class to namespace
• moved some enum definitions to low-level file ID.h

GUI/Models/Data/ApplicationModels.cpp

@@ -111,7 +111,6 @@ void ApplicationModels::writeTo(QXmlStreamWriter* writer)
 void ApplicationModels::readFrom(QXmlStreamReader* reader, MessageService* messageService)
 {
     try {
-
         for (auto model : modelList()) {
             if (model->getModelTag() == reader->name()) {
                 model->readFrom(reader, messageService);
@@ -147,12 +146,12 @@ QVector<SessionItem*> ApplicationModels::nonXMLItems() const
 
 void ApplicationModels::connectModel(SessionModel* model) const
 {
-    if (model) {
-        connect(model, &SessionModel::dataChanged, this, &ApplicationModels::modelChanged,
-                Qt::UniqueConnection);
-        connect(model, &SessionModel::rowsRemoved, this, &ApplicationModels::modelChanged,
-                Qt::UniqueConnection);
-        connect(model, &SessionModel::rowsInserted, this, &ApplicationModels::modelChanged,
-                Qt::UniqueConnection);
-    }
+    if (!model)
+        return;
+    connect(model, &SessionModel::dataChanged, this, &ApplicationModels::modelChanged,
+            Qt::UniqueConnection);
+    connect(model, &SessionModel::rowsRemoved, this, &ApplicationModels::modelChanged,
+            Qt::UniqueConnection);
+    connect(model, &SessionModel::rowsInserted, this, &ApplicationModels::modelChanged,
+            Qt::UniqueConnection);
 }