* Strip out old script glowing in thread management
* Add new tracking mechanism for glowing scripts
* Track parents and use them to determine script glows
* Use top-block for a thread if there's nothing on the stack
* Remove `console.log`
* Always add `next` to block representation
* Add `shadow` property to inputs, to maintain obscured shadows
* Create obscured shadows in SB2 import
* Add XML import of obscured shadows
* Alias SB2 shadow inputs to block inputs
* Add shadow to inputs on "delete inputs" test
* Add a small test to ensure obscured shadows are preserved
* Add more obscured shadow tests
