Save/restore settings dialog (and instance specific settings) window geometry

MultiMC.cpp

@@ -427,6 +427,8 @@ void MultiMC::initGlobalSettings()
 
 	m_settings->registerSetting("ConsoleWindowState", "");
 	m_settings->registerSetting("ConsoleWindowGeometry", "");
+
+	m_settings->registerSetting("SettingsGeometry", "");
 }
 
 void MultiMC::initHttpMetaCache()