Include additional modules though the PlaygroundModule about angular-playground

[jschwarty]

I agree, I'm not a fan of it...but to use the animations module you have to import it in your entry module (or where ever you have BrowserModule because it imports BrowserModule (and not CommonModule). So you can't import it at the sandbox level because Playground is already importing BrowserModule.

Providing a way to add to the PlaygroundModule is something I was thinking through but would probably require some configuration and convention and it felt a little heavy for solving this Animation module story. Most module dependency scenarios can be handled at the sandboxOf level.

But that being said, I'm totally open to coming up with a non-magical way to get the animations module in at that top level. 😎

[jschwarty]

This will get taken care of when #32 gets done. Closing this and referencing it in there.