[4.1] First (of many) to update docs to 4.1 syntax

I didn't update all the docs yet. I'm assuming the helper stuff will change quite a bit with @yguedidi's updates. But it's a good start. @gfosco: you might need to double check the FBMD. It'd be cool if we could preview the compiled version somehow before committing it.

When we get factories implemented we can use those in the "getting started" docs for quick-and-easy examples and then document the more powerful features in the reference docs. :)