Fix the svg:use. For a svg:use, it is a group which include the content it reference. It means that we can not tween it to its origin object directly. Instead, we need to ungroup it and then use the result matrix to generate the tweened transformation matrix. Therefore, we need to concate its matrix to the referenced object. Ad center object when the bbox-x is not available.

<LEFT>		Turn to left.
<RIGHT>		Turn to right.
<UP>		Turn to up.
<DOWN>		Turn to down.
<SPACE>		To Fire.