Further progress towards tenant-specific routing

Ability to follow redirects from integration tests
Route publisher wraps handler with ShellRoute which controls request lifetime scope
ShellRoute at the moment is restricted to "Default" - host and prefix TBD
Route publisher remove-and-insert routes for a specific tenant to allow incremental and repeated shell route publish
Offers a more deterministic knowledge of which shell container is used than just-in-time http context
Removes Autofac default httpmodule, controller factory, httpapplication icontainerprovideraccessor, etc
Adds support for optional ~/Config/Sites.{yourtenantname}.config file for manual per-shell component override
Integration tests capture Orchard and NHibernate trace output. Levels are configurable in orchard.specs diagnostics.config
Concept of IRunningShellTable instroduced. Might not be needed - will be removed if so.

--HG--
branch : dev

src/Orchard.Specs/Hosting/RequestExtensions.cs

@@ -111,6 +111,9 @@ namespace Orchard.Specs.Hosting {
                 if (index == HeaderSetCookie) {
                     _details.ResponseHeaders.Add("Set-Cookie", value);
                 }
+                else if (index == HeaderLocation) {
+                    _details.ResponseHeaders.Add("Location", value);
+                }
                 else {
                     _details.ResponseHeaders.Add("known header #" + index, value);
                 }