autosave periodically when project is dirty

Disconnect from cloud when entering editor mode on someone else's project

Connect to cloud based on hasCloudData

Queue up messages to send ot the cloud server which accumulate before 
the connection is ready. Add tests for new/updated functionality.

simplified autosave code per rschamp's comments; made isShowingSaveable and autosaveIntervalSecs props

Remove color rotation while saving

Update scratch-paint to the latest version 

Add download and retry saving to saving error alert.

Instead of setting 100% width on the message, causing inappropriate wrapping of the button text. Removed the nbsp in the Try Again text

Track "project changed" state in Redux

I do not like how the alert component is hyper specialized for two distinct use cases. It would be much better to refactor the alerts so that the alerter can just fill the alert with whatever they want. But I do not feel comfortable making that refactor because I know ben and evelyn have gone back and forth about these alerts.

updated scratch-l10n in package.json

We have alerts for this now.
Resolves #3893

Update scratch-vm to the latest version 

Listen to the new project changed event from the VM and keep track of the state in Redux.  Update it as appropriate.

Known issue is that the project is marked as "changed" immediately after it's loaded. This is due to asynchronous event emitting while the project data is loaded, and needs an update to the VM to fix.

Prevent arrow/space from scrolling the page

Adding RTL padding to reconnect button on alerts.

better padding, margin in device connection modal

Add unit tests for disconnecting from cloud when viewing a project in editor mode without the ability to save.

Update scratch-vm to the latest version 

Hide entire frame unless the VM has not started