Mark SAV as unmodified upon load

Closes #1076
seems kinda lazy as I didn't bother tracking down the suspect that
modifies the save (presumably the hex seed values); those should load
correctly and not change any bytes.

PKHeX.WinForms/MainWindow/Main.cs

@@ -1357,6 +1357,7 @@ private void openSAV(SaveFile sav, string path)
 
             TemplateFields();
             loadingSAV = false;
+            SAV.Edited = false;
 
             // Indicate audibly the save is loaded
             SystemSounds.Beep.Play();