placeholder for the datatypes i'll need for the new ECS

include/fggl/ds/placeholder.hpp

+/*
+ * This file is part of FGGL.
+ *
+ * FGGL is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * FGGL is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with FGGL.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+//
+// Wrappers for types that probably should be implemented, but can be faked for now.
+// These are placeholders for the more advanced/specialist data structures we should be using, but mocked out using
+// more basic ones.
+//
+
+#ifndef FGGL_DS_PLACEHOLDER_HPP
+#define FGGL_DS_PLACEHOLDER_HPP
+
+namespace fggl::ds {
+
+} // namespace fggl::ds
+
+#endif //FGGL_DS_PLACEHOLDER_HPP