Nancy 2.0.0-clinteastwood feedback

This compiles, but throws a run-time NullReferenceException:

pipelines.BeforeRequest.AddItemToStartOfPipeline((ctx, _) =>
{
    // do stuff
    // Func<NancyContext, Response>, Func<NancyContext, CancellationToken, Response>
    return null;
});

This works:

pipelines.BeforeRequest.AddItemToStartOfPipeline((ctx, _) =>
{
    //do stuff
    // Func<NancyContext, CancellationToken, Task<Response>>
    return Task<Response>.FromResult((Response)null);
});

It took a bit of bashing my head against the wall until I figured it out which is neither super-duper nor happy.

@danbarua thanks. I've opened https://github.com/NancyFx/Nancy/issues/2665 because I want to give the pipeline stuff an overhaul as soon as we've had the time to look at the bootstrapper (which will happen as soon as I've moved us to the new csproj format and that's happening now in #2720)

YAK SHAVING! 😄

This code throw an exception, is this bug?

```C#

public class BaseModule : NancyModule
{
public BaseModule(string url) : base(url)
{
//Custom logic
}
}

public class A : BaseModule
{
public A() : base("urlA")
{

}

}

public class B : NancyModule
{
public B()
{

}

}

System.InvalidOperationException occurred
HResult=0x80131509
Message=Something went wrong when trying to satisfy one of the dependencies during composition, make sure that you've registered all new dependencies in the container and inspect the innerexception for more details.
Source=
StackTrace:
at Nancy.Bootstrapper.NancyBootstrapperBase1.SafeGetNancyEngineInstance() at Nancy.Bootstrapper.NancyBootstrapperBase1.GetEngine()
at Nancy.Owin.NancyMiddleware.UseNancy(NancyOptions options)
at Nancy.Owin.DelegateExtensions.UseNancy(Action1 builder, NancyOptions options) at PiggyBank.Site.Startup.<>c.<Configure>b__2_0(Action1 x) in E:visual_studiopiggy-banksourcePiggyBank.SiteStartup.cs:line 31
at Microsoft.AspNetCore.Builder.OwinExtensions.UseOwin(IApplicationBuilder builder, Action`1 pipeline)
at PiggyBank.Site.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory) in E:visual_studiopiggy-banksourcePiggyBank.SiteStartup.cs:line 31

Inner Exception 1:
TinyIoCResolutionException: Unable to resolve type: Nancy.NancyEngine

Inner Exception 2:
TinyIoCResolutionException: Unable to resolve type: Nancy.Routing.DefaultRequestDispatcher

Inner Exception 3:
TinyIoCResolutionException: Unable to resolve type: Nancy.Routing.DefaultRouteResolver

Inner Exception 4:
TinyIoCResolutionException: Unable to resolve type: Nancy.Routing.RouteCache

Inner Exception 5:
TinyIoCResolutionException: Unable to resolve type: BaseModule

Inner Exception 6:
TinyIoCResolutionException: Unable to resolve type: System.String

Inner Exception 7:
TinyIoCResolutionException: Unable to resolve type: System.Char[]

Inner Exception 8:
ArgumentNullException: Value cannot be null.

```

It's because the base module doesn't have a constructor that the IoC container can satisfy. It doesn't know how to handle string. If the BaseModule Isn't supposed to be called by itself, I suggest you make it abstract...

Old:

Get["post/{id}"] = Get["old/post/{id}"] = p =>{};

New(2.0):

?

Get("post/{id}", MyMethod);
Get("old/post/{id}", MyMethod);

Get("post/{id}", MyMethod);
Get("old/post/{id}", MyMethod);

That usage adds some indirection. I personally don't like that. Not a problem though.

Maybe it is possible to have some method overloads for fluent expression? example:

Get("post/{id}")
.Get("old/post/{id}")
.Post("whatever/{id}", p => { return HttpStatusCode.Ok });

An alternate expression

Get("post/{id}")
.Get("old/post/{id}")
.Post("whatever/{id}")
.Do(p => { return HttpStatusCode.Ok });

I can take a stab at PR if this is desirable