* Add Flow libdef
* Move libdef to flow folder in root
* Update libdef with some refinements discovered while writing test
Mostly refining navigator config types. In the past when we tried it we got in-repo Flow errors. With a libdef we can now assert it as true!
* Get rid of all imports in libdef and refine some types
* Update .eslintrc to allow compile.
* Resolve .web.js extension
* Look for __DEV__ on global
Fixes ReferenceError when not in the React Native environment.
* Replace __DEV__ at compile time via babel
* Don't try to lint a website build
