Pass a `stageSize` property down from a centralized `MediaQuery` in the
GUI component, and control the size of the stage and all surrounding
elements based on that value. Note that this is a pure property and is
not stored in the Redux state, since we gain access to the results of
the media query during `render()` and we shouldn't change Redux state
during `render()`.

Some stage-adjacent elements don't yet react correctly to the smallest
stage size.

Update scratch-paint to the latest version 

Update scratch-blocks to the latest version 

Prevent pushing tutorial cards beyond width

Move z-index values to separate file

Update chromedriver to the latest version 

Fix "Opening the backdrop library causes the stage backdrop editor to become selected"

Fix sprite selector scroll bar

Change CSS

Update scratch-blocks to the latest version 

Update classnames to the latest version 

Update scratch-paint to the latest version 

Merge smoke changes for 6/8/18 iteration to back into develop

Revert "Add when touching hat"

This reverts commit 94915a9a.

Add when touching hat

Update scratch vm

Update scratch-blocks to the latest version 

Update scratch-paint to the latest version 

Update scratch-paint to the latest version 

Update scratch-svg-renderer to the latest version 

Update chromedriver to the latest version