use blue creating screen for new projects; revised alert text for copy, remix; saving messages don't dismiss alerts

Has cloud permission

Update scratch-paint to the latest version 

Fix stage wrapper not setting dir="ltr/rtl" property, buttons look wrong

Update scratch-blocks to the latest version 

Include polyfill for promise.finally so Edge can load projects

Cloud Variable Rate Limit

Update scratch-blocks to the latest version 

Update scratch-vm to the latest version 

Update scratch-l10n dependency

save before saving as a copy

New scratch-l10n includes a script for pushing to transifex. Update package.json to use the new script for pushing the source to transfiex..

Closes #3910

Revise alerts code to clarify and reorganize alert type handling

delete existing translations before building translations, to avoid errors

Remove setTimeout for reattaching workspace block listener.

It was causing a bug where switching tabs and adding a sprite would make the workspace blocks not work. Needs investigation.

Send snapshots from the renderer to be saved as project thumbnails

autosave periodically when project is dirty

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