logic: add name delimiter to NameHierarchy

* NameHierarchy now looks like this: <delimiter>\tm<all the rest>
* made new baseclasses for SettingsMigration and SettingsMigrator
* Use the migration system for SqliteBookmarkStorage as well

src/lib/data/SqliteStorageMigrationLambda.h

@@ -0,0 +1,19 @@
+#ifndef SQLITE_STORAGE_MIGRATION_LAMBDA_H
+#define SQLITE_STORAGE_MIGRATION_LAMBDA_H
+
+#include <functional>
+
+#include "data/SqliteStorageMigration.h"
+
+class SqliteStorageMigrationLambda: public SqliteStorageMigration
+{
+public:
+	SqliteStorageMigrationLambda(std::function<void(const SqliteStorageMigration*, SqliteStorage*)> m_lambda);
+	virtual ~SqliteStorageMigrationLambda();
+	virtual void apply(SqliteStorage* migratable) const;
+
+private:
+	std::function<void(const SqliteStorageMigration*, SqliteStorage*)> m_lambda;
+};
+
+#endif // SQLITE_STORAGE_MIGRATION_LAMBDA_H