[Fixes #1378] Added few WebAPI like Action Results - Part 1

@rynowak 
Should these set the `StatusCode` property in the constructor instead? As is stands, a user specified status code always get over written by these hardcoded values.

```
var result = new CreatedAtRouteResult(...)
{
   StatusCode = 204
};
return result;
```

Expected: 204 status code
Actual: 201