Updating Body.rotate to use the parameter passed in

Please let me know if I am setting this improperly. This is the script I used to test the change.

```coffeescript
Engine = Matter.Engine
World = Matter.World
Body = Matter.Body
Bodies = Matter.Bodies

engine = Engine.create document.body, {render: {options:{showAngleIndicator: true, wireframes: false}}}
testObjectToRotate = Bodies.polygon 250, 250, 3, 20, isStatic: true
World.add engine.world, testObjectToRotate
Engine.run engine

# Verify the triangle rotates.
Body.rotate testObjectToRotate, 20
```