With jscodeshift thank God

* Set editing target when double clicking on sprite in stage

* rename double clicker handler and add comment

Attaching the storage module in `vmListenerHOC` means it can propagate
down to the GUI, stage, and blocks naturally. The default VM property
value has been removed from those places so that we're not instantiating
extra VM instances any more. Instead, using one of those components
outside of the `vmListenerHOC` framework will require providing a VM
instance as a property.

There are a handful of places where the GUI code could use the storage
module directly; converting those is for a later change.

* WIP: drag states in stage component

* WIP: Hacky drag canvas

* Update sprite position on drag

Use VM to put sprite into drag state and update the sprite's position while dragging.

Temporarily don't use the drawable data to drag a new canvas, this can happen whne we have somewhere to drag the sprite to.

`getBoundingClientRect` forces WebKit to recalculate the layout ("force reflow"), so cache the canvas bounding box rather than getting it on every mouse event.

The inline css method gives us nothing that CSS modules can't give us. This puts the project more in line with the way www works, and makes CSS actually readable.

Using class names gives us full control of the modal styles.

So that it's easier to use these standalone.

And use instanceOf for the vm prop type

Move behavior-related components to "containers", leave presentation components in "components".

Confine the logic for adding/removing event listeners between the VM and the components to the relevant components.  While this tightens the coupling between the component and the environment, it makes using the individual components more self-contained.

Use fewer refs, these had weird behavior that caused the order of components to matter.
Attach events eagerly, as soon as the necessary objects are available.
Make VMManager an actual class instantiated with a VM so we don't have to pass it to every method.
Use bindAll everywhere for convenience.

Update webpack config and vm usage to match updates in scratch-vm