[Finishes 67229902]: add whenGameStarts, setSpeed blocks, + misc bug fixes
merge
[Finishes 67229902, Partial 67232618]: add whenGameStarts, setSpeed blocks, + misc bug fixes
PR feedback: s->speed d->dir
Merge pull request #438 from code-dot-org/pivotal_67229902_67232618

Pivotal 67229902 67232618 + misc bug fixes