More RESTful HTTP handling

Looking at the docs for `haxe.Http` (which is really HttpRequest) and `php.Web` right now, I think there's a bias towards GET and POST requests. Probably because REST wasn't a well known concept when those were created. Some examples:

* You can _send_ a `Http.customRequest` but I don't see how you would handle _receiving_ a new [PUT via PHP](https://www.php.net/manual/en/features.file-upload.put-method.php) or really anything but a GET and POST request.

* There's the unfortunately named `php.Web.getPostData` which actually expects form-encoded data, so it's really `php.Web.getFormData`. It's a nice helper method, but there's nothing inherent to a POST request that wouldn't allow you to send any kind of content, like XML or JSON.

* `haxe.web.Request.getParams` returns "POST parameters", which probably again assumes form-urlencoded data has been sent.

Is it an option to change/expand any of that at this point or is it too late? As is, it looks like Haxe doesn't lend itself to writing a RESTful webservice, at least not with PHP as target. I know PHP isn't "hip" anymore, but I thought I should ask. Maybe I could even help, if there's interest, but I'm not sure if I'm qualified.