Massively improved Config Key/Joy Mappings screen.

Warning is dismissable now, and cursor does not start in a position that will change a setting.
New special actions added:  ClearToDefault, ReloadFromDisk, SaveToDisk, SetListMode.  Exit is a special action.
Player is prompted to save when exiting screen instead of saving after every action.
Special actions fallback on Graphics/SMC action if they don't have their own.
Moved SMC overlay to Graphics/SMC warning.
Metrics for configuring input lock time, warning autodismiss time, lines visible, and NoSetListPrompt autodismiss time.
Header row added for cursor to start on.
ScreenMapControllers2 deleted as obsolete.
BitmapText:maxwidth changed to factor the zoom of the actor into the calculation.

src/InputMapper.cpp

@@ -654,6 +654,13 @@ void InputMapper::SaveMappingsToDisk()
 	m_mappings.WriteMappings( m_pInputScheme, SpecialFiles::KEYMAPS_PATH );
 }
 
+void InputMapper::ResetMappingsToDefault()
+{
+	m_mappings.Clear();
+	UpdateTempDItoGI();
+	AddDefaultMappingsForCurrentGameIfUnmapped();
+}
+
 static LocalizedString CONNECTED			( "InputMapper", "Connected" );
 static LocalizedString DISCONNECTED			( "InputMapper", "Disconnected" );
 static LocalizedString AUTOMAPPING_ALL_JOYSTICKS	( "InputMapper", "Auto-mapping all joysticks." );