NancyFx/Nancy — pull request #1053 by damianh (2013-03-30 09:11:05+00:00)
Title: OWIN pass-through support and general owin host improvements

When using Nancy in OWIN, can support pass through if the specified http status codes passed in through a new configuration object occur.

```csharp
builder.UseNancy(options =>
{
options.Bootstrapper = new TestBootstrapper();
options.PassThroughStatusCodes = new[] {NancyHttpStatusCode.NotFound};
})
.UseEtc()
````
Includes changes to support this in NancyOwinHost and some other changes in INancyEngine & NancyEngine to support Tasks. See commits and comments for more info.