Add Async.All

[evilsoft]

More scope creep huh?

This addresses one part of Issue#39 and implements Async.all.

And what kind of me would I be if I did not add a bunch of other stuffs off the books (need to stop doing this). In addition to implementing Async.all I threw in this other stuff :smh:

• Added an Async.fromNode that will take in any CPS (Continuation Passing Style) function and wrap it all up in an Async ready to be forked.
• Added a new predicate function named isFoldable.
• Updated functions that rely on a Foldable to use the new predicate for their type checks.
• Cleaned up some Async.fromPromise 👓

[evilsoft]