[Pas2js] Async, AWait

[Michael Van Canneyt]

On Thu, 28 May 2020, Mattias Gaertner via Pas2js wrote:

> Hi all,
>
> pas2js trunk now supports async procedures and await functions.
> This can greatly simplify writing asynchronous code, like starting a
> download, handle the result, depending on the result download the next
> piece and so forth.
> Formerly you needed some (anonymous) functions for that. Now you can
> write asynchronous code, that looks like normal, synchronous
> code.
>
> https://wiki.freepascal.org/pas2js_AsyncAWait


I have added the demos from the wiki page to the demo dir in the sources,
fixed a small error in one of the demos.

Enjoy !

Michael.