Add SaveRom to MasterEditor, rename Rom::isLoaded to is_loaded

src/app/editor/modules/gfx_group_editor.cc

@@ -215,8 +215,6 @@ void DrawPaletteFromPaletteGroup(gfx::SNESPalette &palette) {
 }  // namespace
 
 void GfxGroupEditor::DrawPaletteViewer() {
-  // TODO: Implement palette viewer
-  static PaletteEditor palette_editor;
   static uint8_t selected_paletteset = 0;
 
   gui::InputHexByte("Selected Paletteset", &selected_paletteset);

src/app/editor/modules/gfx_group_editor.h

@@ -47,6 +47,8 @@ class GfxGroupEditor : public SharedROM {
   uint8_t selected_roomset_ = 0;
   uint8_t selected_spriteset_ = 0;
 
+  PaletteEditor palette_editor_;
+
   gui::Canvas blockset_canvas_;
   gui::Canvas roomset_canvas_;
   gui::Canvas spriteset_canvas_;

src/app/editor/modules/palette_editor.cc

@@ -91,7 +91,7 @@ void PaletteEditor::ResetColorToOriginal(
 }
 
 absl::Status PaletteEditor::DrawPaletteGroup(int category) {
-  if (!rom()->isLoaded()) {
+  if (!rom()->is_loaded()) {
     return absl::NotFoundError("ROM not open, no palettes to display");
   }