External UMD module is unable to resolve RxJS after prod build

[brian428]

Minko, I know you're a busy guy, but if you have a moment, could you look through this issue I've opened over on the angular2-toaster project? I've got an issue that has stumped me as well as the project creator. I can't tell if it's an issue with his UMD bundle or an issue with the way the seed project maps RxJS for prod builds.

I won't ask you to spend a bunch of time on it, but I figured you might have some immediate ideas just from looking over the symptoms.

Stabzs/Angular2-Toaster#131

Thanks!