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.

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

Remove the WebGL checks from the error boundary. Instead, just do not
render the stage if it is not supported.

Additionally render the canvas at a multiplier of the device pixel
ratio, so we get hidpi images for supported screens. The fixed CSS
sizing allows us to do that.

The problem was that on Edge, flexbox apparently can grow canvas
elements, whereas on Chrome/FF the canvas width/height is respected. No
problem, we can set the width/height in CSS to fix it, which
conveniently allows us to also fix the low-res-on-retina-screens problem
at the same time.

Add Error Boundary (has componentDidCatch method) to handle WebGL errors and display an informative message.