Add 'async' dependency
Add 'async' dependency

Primarily for the 'parallel' function, which we've
hacked out a number of times already. Might as 
well use a maintained lib.
ellipsonic/circle-blvd,ellipsonic/circle-blvd,holmwell/circle-blvd,myersg86/circle-blvd,ellipsonic/circle-blvd,ellipsonic/circle-blvd,myersg86/circle-blvd,holmwell/circle-blvd,secret-project/circle-blvd,myersg86/circle-blvd,secret-project/circle-blvd,holmwell/circle-blvd,secret-project/circle-blvd,myersg86/circle-blvd,secret-project/circle-blvd,holmwell/circle-blvd