Handle events for the uploader and transcoder better

[jellegerbrandy]

Here is what I think it should look like (I have seen this pattern somewhere but cannot find it, it would be good to have a reference):

uploader.upload(file) shoudl return a Promise (as it already does) that is also an EventEmitter.

So that means that the usage pattern would be something like this:

let foo = uploader.upload(file)
// foo is  a promise that is pedning until uploading and transcoding is finished

i // foo is also an EventEmitter that emits events relative to this upload, that can be subscribed to
foo.on('UploadFinished', dosomething)
foo.on('Progress', function(progress) { console.log(progress })

This is nicer than what we have now (passing callbacks for each event), and just as easy to program (instead of calling onSomething(...args) in the code, we write `promsie.emit('Something', ...args)

[jellegerbrandy]

@ya7ya , what do you think?

[ya7ya]

@jellegerbrandy I got it. I'll implement that 👍