Allow single project configs to specify feature flags (#3840)
Allow single project configs to specify feature flags (#3840)

Summary:
I'm hacking on a side project, and I wanted to try to get Relay Resolvers to work but I could not enable them using the single project config.

Pull Request resolved: https://github.com/facebook/relay/pull/3840

Reviewed By: rbalicki2

Differential Revision: D34964872

Pulled By: captbaritone

fbshipit-source-id: df47f06b75e99daa0340e71b527b7df238bfa140

voideanvalue/relay,voideanvalue/relay,wincent/relay,facebook/relay,xuorig/relay,kassens/relay,wincent/relay,voideanvalue/relay,facebook/relay,facebook/relay,wincent/relay,facebook/relay,kassens/relay,facebook/relay,kassens/relay,xuorig/relay,xuorig/relay,xuorig/relay,wincent/relay,wincent/relay,voideanvalue/relay,xuorig/relay,voideanvalue/relay,kassens/relay,kassens/relay,kassens/relay,xuorig/relay,voideanvalue/relay,facebook/relay,wincent/relay