Update to RxJS 5

[ahstro]

I wanted to work through the koans, but since I'm using RxJS 5 and they were in RxJS 4, I decided to convert them as well. I'm not sure if this is wanted, but thought I might as well open a PR, if not for the merge than at least for others to see that there's a RxJS 5 version available.

I took the liberty to enable ES6 and stage-0 JavaScript, just for my own enjoyment, so if that's not desirable.. well, okay :)

Also, there are about three koans from the original that have not been converted (they're commented out) because the operators used have not been implemented yet and it's almost 2 at night, so I'm not going to look into fixing those right now.

Thanks for this project, it was fun working through :)

[adrianmcli]

@ahstro have you had any luck converting the rest of it? I'd be happy to help out once I get there (I just started the first file tonight). Maybe once it's done, @mattpodwysocki would be more inclined to merge this in.

[ahstro]

I haven't had a look at it and don't really have the time right now, so if you're willing to look at it, that'd be great :)