Get the mime-type for the file from the blob

Greenkeeper/scratch render 0.1.0 prerelease.20190813154945

Closes #4992

Depends on the VM change that sets the mime-type

Fix duplicate running blocks by removing pointer-events: none

Add webpack resolver to eslintrc so linter doesn't give false positive noUnresolved errors

Revert "Make delete button accessible"

Update scratch-vm to the latest version 

Fix issue where context menu wouldn't come back after dragging

Update scratch-l10n to the latest version 

Update paint

Fix saving after recording a sound

Update scratch-blocks to the latest version 

Add play buttons to sound library tiles for touch

Make delete button accessible

Add Jest-specific linting rules

Adding this caught a couple of important things:
- The sound integration tests have a `.only` in them
- The project-saver-hoc tests had two tests with the same description, causing possible confusion if that test broke

Also noticed that Delete aria label was not localized.

Update scratch-l10n to the latest version 

Use the classNames feature to include/exclude a class based on a boolean instead of ternary operator