Move exception handling to request processor, action details to request context
Scope RequestContextBuilder to the request.

Scoping it as a singleton means that the ActionInvocation instances will all use
the parent IOC container instead of the child, which is not what we want.
Drill down through outer AggregateExceptions.
Skeleton for NustacheViewEngine.
IApplicationContext interface.
Redundakitty
Move IResource and IMimeTypes to Dolstagis.Web.Static namespace.

We're not going to change the implementations of these classes. However, I am
going to change everything else in the Static namespace.
Created a VirtualPath class so we know exactly what we're dealing with.
HttpRequest uses VirtualPath instead of string for virtual paths.
Application uses VirtualPath.
VirtualPath.ToString()
Status.ToString()
Comparison methods on VirtualPath.
Delegate getting the app-relative path to the VirtualPath class.