"Hello World"-example should match its spec ( Fixes #476 )

[meisterlampe]

Hi,

I just started experimenting with swagger and followed the steps in the Readme.
When I generated a C#-Client for the "Hello World"-Example-Server, it wasn't working out of the box, because the server just returns "Hello, stranger" instead of "{ "message": "Hello, stranger" } as specified in the swagger-spec.
I first created an issue in the swagger-codegen-repo (see swagger-api/swagger-codegen#4816), which was the wrong place for reporting :)

This is only a minor bug I know, but the example should work out of the box. This pull request should make the example match its spec again. It should fix: #476

[meisterlampe]

Sorry for all the commits. I had to fix every single file using the web frontend O:)
Feel free to squash them into a single one.