Core: Use a C++11 way of providing a singleton

This is thread safe and guarantees Core will always be cleaned upon exit

src/Main/Core.cpp

@@ -174,3 +174,10 @@ Project* Core::currentProject()
 {
     return m_currentProject;
 }
+
+Core*
+Core::getInstance()
+{
+    static Core core;
+    return &core;
+}

src/Main/Core.h

@@ -39,9 +39,7 @@ namespace Backend
 
 #include <QObject>
 
-#include <Tools/Singleton.hpp>
-
-class Core : public QObject, public Singleton<Core>
+class Core : public QObject
 {
     Q_OBJECT
 
@@ -60,6 +58,8 @@ class Core : public QObject, public Singleton<Core>
         bool                    restoreProject();
         bool                    isProjectLoaded();
 
+        static Core*            getInstance();
+
     signals:
         /**
          * @brief projectLoaded Will be emited right before a project starts loading.
@@ -86,8 +86,6 @@ class Core : public QObject, public Singleton<Core>
         AutomaticBackup*        m_automaticBackup;
         Workspace*              m_workspace;
         Project*                m_currentProject;
-
-        friend class Singleton<Core>;
 };
 
 #endif // CORE_H

src/Main/main.cpp

@@ -212,7 +212,6 @@ VLMCmain( int argc, char **argv )
 #else
     int res = VLMCCoremain( argc, argv );
 #endif
-    Core::destroyInstance();
     return res;
 }