Adding vector config clarification (#216)

Making it a little clearer that you can use vector config options with vector values.

docs/animated.md

@@ -145,6 +145,8 @@ For example, when working with horizontal scrolling gestures, you would do the f
 
 ## Methods
 
+When the given value is a ValueXY instead of a Value, each config option may be a vector of the form `{x: ..., y: ...}` instead of a scalar.
+
 ### `decay()`
 
 ```javascript