TaskModel: Sort task by id

Makes it easier to later find the task again, and does actually not
change the order in the normal case

Change-Id: I2f36f2e7a6ab52c06e35be22820438a809ecb012
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>

src/plugins/projectexplorer/taskmodel.h

@@ -116,7 +116,7 @@ private:
     };
 
     QHash<Core::Id,CategoryData> m_categories; // category id to data
-    QList<Task> m_tasks;   // all tasks (in order of insertion)
+    QList<Task> m_tasks;   // all tasks (in order of id)
 
     QHash<QString,bool> m_fileNotFound;
     int m_maxSizeOfFileName;