Avoid double-delete on close

src/core/icourse.h

@@ -56,8 +56,8 @@ public:
     virtual QUrl file() const = 0;
 
 protected:
-    ICourse(QObject *parent = nullptr)
-        : QObject(parent)
+    ICourse()
+        : QObject()
     {
     }
     virtual void setSelf(std::shared_ptr<ICourse> course) = 0;

src/core/ieditablecourse.h

@@ -44,8 +44,8 @@ public:
     virtual bool isModified() const = 0;
 
 protected:
-    IEditableCourse(QObject *parent = nullptr)
-        : ICourse(parent)
+    IEditableCourse()
+        : ICourse()
     {
     }
 };

src/core/resources/courseresource.cpp

@@ -97,7 +97,7 @@ void CourseResource::setSelf(std::shared_ptr<ICourse> self)
 }
 
 CourseResource::CourseResource(const QUrl &path, IResourceRepository *repository)
-    : ICourse(repository)
+    : ICourse()
     , d(new CourseResourcePrivate())
 {
     QQmlEngine::setObjectOwnership(this, QQmlEngine::CppOwnership);