add option to save unused patterns

closes #106

also prepare for the pattern manager window

src/gui/patManager.cpp

@@ -0,0 +1,37 @@
+/**
+ * Furnace Tracker - multi-system chiptune tracker
+ * Copyright (C) 2021-2022 tildearrow and contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "gui.h"
+#include "misc/cpp/imgui_stdlib.h"
+#include "IconsFontAwesome4.h"
+#include <imgui.h>
+
+void FurnaceGUI::drawPatManager() {
+  if (nextWindow==GUI_WINDOW_PAT_MANAGER) {
+    patManagerOpen=true;
+    ImGui::SetNextWindowFocus();
+    nextWindow=GUI_WINDOW_NOTHING;
+  }
+  if (!patManagerOpen) return;
+  if (ImGui::Begin("Pattern Manager",&patManagerOpen,globalWinFlags)) {
+    ImGui::Text("Hello World!");
+  }
+  if (ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows)) curWindow=GUI_WINDOW_PAT_MANAGER;
+  ImGui::End();
+}