Node/express internal modules

node.d.ts and express.d.ts have many external module declarations than lack matching internal module declarations. For example, node.d.ts has `declare module "http" {...}`, but there is no corresponding `declare module NodeHttp {...}`.

This is a pain for applications that want to extend the given type definitions and get intellisense and type checking. For example, if express defined its types with internal modules, you could extend the definition of express's Request type in your own app's definition file with something like:
```
///<reference path="express.d.ts" />
declare module ExpressStatic {
    export interface Request {
        transaction: DbTransaction;
    }
}
```

This pull request addresses the above problem, adding corresponding internal modules to all external modules. It won't affect existing code, but it will enable the above type of usage which is not possible with the current definitions.