objdiff-cli diff & report changes, support .splitmeta object section

- Add `objdiff-cli report changes` for diffing two reports
- Unify some click-to-highlight logic between CLI and GUI
- Load .splitmeta section for extra object metadata (original virtual addr, etc)
- More work on objdiff-cli diff

objdiff-gui/src/views/symbol_diff.rs

@@ -143,6 +143,12 @@ fn symbol_context_menu_ui(ui: &mut Ui, symbol: &ObjSymbol) {
             ui.output_mut(|output| output.copied_text = symbol.name.clone());
             ui.close_menu();
         }
+        if let Some(address) = symbol.virtual_address {
+            if ui.button(format!("Copy \"{:#x}\" (virtual address)", address)).clicked() {
+                ui.output_mut(|output| output.copied_text = format!("{:#x}", address));
+                ui.close_menu();
+            }
+        }
     });
 }
 
@@ -161,6 +167,12 @@ fn symbol_hover_ui(ui: &mut Ui, symbol: &ObjSymbol, appearance: &Appearance) {
                 format!("Size: {:x} (assumed)", symbol.size),
             );
         }
+        if let Some(address) = symbol.virtual_address {
+            ui.colored_label(
+                appearance.highlight_color,
+                format!("Virtual address: {:#x}", address),
+            );
+        }
     });
 }