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 

Adds unit tests for this HOC.

Use PureComponent instead since it is a simple shouldComponentUpdate check now.

Update scratch-vm to the latest version 

Move the mask on the audio meter outside the SVG for repaint performance

Remove the redux throttle for targets update.

Disable target updates while sound recording

This fixes the root cause of #2858, which is caused because we are rendering the sound editor based on the GUI editing target data, but retrieving the sound based on the vms editing target data. The throttle of the redux action was causing those to get out of sync while a project was running.

The throttle is not needed because the vm runtime already batches those updates at 30 fps. The updates that come from top-level actions like switching sprites go out immediately.

This is also a minor performance boost, because there was a few ms being spent in setting and checking timers that were not needed.

Closes #4408

Improve sound editor performance with longer sounds

chore(package): update scratch-vm to version 0.2.0-prerelease.2019011…