Support Customizing Image with UIBarPosition and UIBarMetrics

[JustinJiaDev]

A few methods haven't been implemented yet.

UIToolbar

func setBackgroundImage(_ backgroundImage: UIImage?, forToolbarPosition topOrBottom: UIBarPosition, barMetrics: UIBarMetrics)
func setShadowImage(_ shadowImage: UIImage?, forToolbarPosition topOrBottom: UIBarPosition)

UIBarButtonItem

func setBackButtonBackgroundImage(_ backgroundImage: UIImage?, for state: UIControlState, barMetrics: UIBarMetrics)
func setBackgroundImage(_ backgroundImage: UIImage?, for state: UIControlState, barMetrics: UIBarMetrics)
func setBackgroundImage(_ backgroundImage: UIImage?, for state: UIControlState, style: UIBarButtonItemStyle, barMetrics: UIBarMetrics)

UISegmentedControl

func setImage(_ image: UIImage?, forSegmentAt segment: Int)
func setBackgroundImage(_ backgroundImage: UIImage?, for state: UIControlState, barMetrics: UIBarMetrics)
func setDividerImage(_ dividerImage: UIImage?, forLeftSegmentState leftState: UIControlState, rightSegmentState rightState: UIControlState, barMetrics: UIBarMetrics)

UISearchBar

func setBackgroundImage(_ backgroundImage: UIImage?, for barPosition: UIBarPosition, barMetrics: UIBarMetrics)
func setImage(_ iconImage: UIImage?, for icon: UISearchBarIcon, state: UIControlState)
func setScopeBarButtonDividerImage(_ dividerImage: UIImage?, forLeftSegmentState leftState: UIControlState, rightSegmentState rightState: UIControlState)

UIStepper

func setDividerImage(_ image: UIImage?, forLeftSegmentState leftState: UIControlState, rightSegmentState rightState: UIControlState)