Update animations.md

[Supercodegames]

Added small note under #### Method 1: Pick an Image. Note:

In this instance, we're assuming you've already got an Actor open in the Actor Editor. Note however, that starting with Stencyl 3.4, Stencyl allows you to just drag a animation to the actor dashboard and Stencyl will create a actor with that animation. This is useful when you want to create a lot of actors at once.