Echo JS 0.11.0

`async` spec is finalized and is implemented in Edge 14 (behind a flag) and Chrome 52 (52-54 behind a flag, 55 enabled by default).

We will have to see about object rest/spread. It just got upgraded to Stage 3, so the spec is considered complete, but may not have full test suites yet. Little work goes into implementation until the spec is complete.

https://tc39.github.io/process-document/