Update flux typings (#9592)

* Make fbemitter a namespace

* Tighten up typing of flux

* Update flux tests

* Address code comments

* Fix RealOptions interface

fbemitter/fbemitter.d.ts

@@ -3,7 +3,7 @@
 // Definitions by: kmxz <https://github.com/kmxz>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
-declare module 'fbemitter' {
+declare namespace FBEmitter {
     
     export class EventSubscription {
         
@@ -64,4 +64,8 @@ declare module 'fbemitter' {
          
     }
     
-}
+}
+
+declare module 'fbemitter' {
+    export = FBEmitter;
+}