Should help with smaller screen sizes, where the ratio is different (like some chromebooks)

I also suspect this will fix some of the times when the menu
mysteriously stayed open, because it was being re-rendered for by
mistake.

This makes it possible to use on iOS/touch

Add duplicate button. Pass the costume ID to paint (the previous costume ID used matches when duplicate is used.) When switching to the costume tab, open the current costume.

Improvements to error state: input outline shows with or without focus, and added new error div which shows if there's an error, but goes away if the user starts changing what they had submitted in the input. Removing a lot of code surrounding the tooltip which has now become unnecessary.

Import input now shows error state w/orange border around input and tooltip with static error message.

Initial SB2 Import UI (button in preview modal + import modal that can load projects via url). Preliminary validation on url, still needs error handling.

Images are draggable by default, but when used within buttons or as
clickable elements, they should not be draggable because starting a drag
accidentally prevents the click event.

Since we will be adding more interactivity, the active state will
eventually pop the menu open, so I'm not worried about accessibility of
this right now.

This is a long standing issue with how iOS deals with scrollable
elements within a fixed area. This was a helpful resource
https://davidwalsh.name/scroll-iframes-ios