Use modular async

[dignifiedquire]

• parallel and each => run-parallel
• series and eachSeries => run-series
• parallelLimit and eachLimit => run-parallelLimit
• setImmediate => global.setImmediate (shimmed through core-js already)
• queue => need more research

[daviddias]

Note: Use async 2.0 instead

[daviddias]

Anything blocking this one?

[dignifiedquire]

As the referenced commit says this is done in #25

[dignifiedquire]

Tracking in #25, closing here.