I know we will want to change this eventually, so I added comments about that. But the next commit originally contained an inadvertent change to this functionality, so I wanted to add an integration test so that when we do change it, we

It looks like an "test.only" was left in on one of these tests by mistake.

Need to store the rendered xml because the props can change while the blocks tab is hidden, but we re-render based on what was rendered, not the previous props (which may not have been rendered).

This is similar to the `ThrottledPropertyHOC` in that there may be prop changes that do not get rendered, but in this case for a different reason.

This increases the performance of switching between code and other editor tabs, as well as improving the "See Inside" performance. It makes switching to the code tab as fast as switching between sprites.

Avoid double toolbox update on mount and when setting language

Move rounding into sprite info to improve performance

chore(package): update scratch-vm to version 0.2.0-prerelease.2019012…

Update scratch-render to the latest version 

Update scratch-vm to the latest version 

Update scratch-blocks to the latest version 

It also avoids repeating the costly object spread, which becomes a problem for projects with a lot of sprites

Closes #4443

Use fontInliner instead of entire SVGRenderer for showing costume tiles.

Sprite library animations no longer update the entire library state on every costume change

chore(package): update scratch-blocks to version 0.1.0-prerelease.154…

Update scratch-render to the latest version 

Update scratch-svg-renderer to the latest version 

Closes #4426

The fontInliner from the scratch-svg-renderer was changed recently to work entirely on strings, so we can use that instead of parsing/loading/possibly drawing/stringifying the entire SVG. 

This does not address the size-1 cache issue where the cache is invalidated any time there is more than 1 sprite. But that can be handled later.

Using the 4x CPU slowdown in chrome dev tools, on a simple costume that just has a single text element the getCostumeUrl time goes from 10ms to 1ms, very important for updating in a timely way.

Fix test broken in #4422 by updating the snapshot.

Add container with overflow hidden to prevent scrollbars from playhead

Update l10n

Revert "chore(package): update scratch-l10n to version 3.1.20190123150639"

chore(package): update scratch-l10n to version 3.1.20190123150639

Throttle costume and watermark updates

Update scratch-blocks to the latest version