jasonmills

We should probably support all the variations since we want to also support the lifecyle patten. ```go // *Foo must be provided by New func (*Foo) Start() {} fx.Annotate(New, fx.OnStart(...

I'm going to abandon this PR and separate it into some smaller chunks since it has some scope creep.

@abramlab can you rebase this PR to make sure there aren't any conflicts against the latest changes to the shutdown and signal logic: https://github.com/uber-go/fx/commit/b379e132182b47a3f2400212e136898575665154