update firebase/firebase.d.ts to version 2.0.2
Add name to "Definitions by".
Merge branch 'master' of https://github.com/borisyankov/DefinitelyTyped into firebase.d.ts
Modify the "Firebase" declaration to interface by decomposing class.
Unify without the "I" prefix.
Merge pull request #3109 from in-async/firebase.d.ts

update firebase/firebase.d.ts to version 2.0.2