WIP implementation for WeDo2 blocks
WIP implementation for WeDo2 blocks

Hat blocks are still TBD.
Motor blocks assume a `util` argument which has methods for `yield()`
and `done()`.

TheBrokenRail/scratch-vm,LLK/scratch-vm,LLK/scratch-vm,TheBrokenRail/scratch-vm,LLK/scratch-vm