tv4.async vanilla implementation

[SamuelMarks]

PR isn't ready, just wanted to start the discussion.

---

Justification: Everyone has uses a different library for there project, e.g.: Angular, MooTools, JQuery. Rather than write one for each, let's just use vanilla JavaScript. Standards are (finally) supported on all browsers with sufficient conformance to enable this.

[sebilasse]

It is a good idea to make the shipped async implementation dependency free.

However : We could keep the jQuery one because everyone can choose then.
What I did is an implementation based on the future of dojo : https://github.com/dojo/core (request).
Could also contribute it. Benefits:
• works also native in TypeScript projects
• works in node.js and browser, finds best transport
• works also for local file resolution (in node.js, tries to resolve relative pathes)
• can handle redirects
• is promise based if no callback provided (because we need promises)

[SamuelMarks]

I do love TypeScript, sure thing write it up in a new patch 👍