Add a refresh function to TutorialCoachMark and add unFocusAnimationDuration to TargetFocus

[LouShi]

Add a refresh function to TutorialCoachMark

This can be called to update the position and size of the current target. It can be called after the orientation changed #66

Add unFocusAnimationDuration to TargetFocus

Customize unFocusAnimationDuration for each target.