1. Areas defined by the Area attribute
2. Areas are a routeconstraint on the actiondescriptor
3. Areas find pages through route values
Other changes:
1. Remove Path from ActionDescriptor - It doesn't make sense with this change
2. Add sample Area
- use Microsoft.AspNet.Mvc.Rendering namespace throughout assembly
Also
- move `IdAttributeDotReplacement` from `TagBuilder` to `HtmlHelper`
- remove commented-out code in `HtmlHelper`
- use `var` and `[NotNull]` more
- `String` -> `string`
- correct Resources references; add missing resources
This follows a similar pattern to html helpers - a minimal basis interface
that performs the main functionality, and a set of extension methods that
make up the rich API.