Update offsets for Sprite Sheet Animations

Realized that MovieClip wasn't updating / offsetting the position of the texture when the MovieClip was running. This is for Sprite sheets with Trim Mode set to Trim (smallest image sizes).

I'm not sure if the anchor property is the best way to offset textures but that how I ended up implementing it.

I also added a property to ```Texture``` called anchor which will update the ```Sprite```'s anchor position.

For the developer having pivot and anchor on Sprite in some ways is a bit redundant so this is why I ended up using ```Sprite.anchor``` to offset the texture.