My extensions for the GoKit tween library for Unity 3D (https://github.com/prime31/GoKit). It contains tweens for achorPositions (tween all four anchors relative to their "center") and the anchored position (http://docs.unity3d.com/ScriptReference/RectTransform-anchoredPosition.html).
It is implemented with c# extension methods to GoKit (https://msdn.microsoft.com/en-us/library/bb383977.aspx).
Usage is similar to the translation tweens in GoKit. The target object needs to have a RectTransform.
Import the extension with using GeosGoKitExtension;
anchorPositions(this GoTweenConfig goTweenConfig, Vector2 endValue, bool isRelative = false)
Vector2 targetPos = new Vector2( 0.0f, 0.0f);
var anchorPositionsTween = new GoTween(your2dObject.transform, 1.0f, new GoTweenConfig().anchorPositions(targetPos, false));
anchoredPosition(this GoTweenConfig goTweenConfig, Vector2 endValue, bool isRelative = false)
Vector2 targetPos = new Vector2( 0.0f, 0.0f);
var anchorPositionsTween = new GoTween(your2dObject.transform, 1.0f, new GoTweenConfig().anchoredPosition(targetPos, false));
Simply add the folder to your script assets in Unity.