Added Durandal451 project template.

This PR adds a ASP.NET 4.5.1 template (Durandal451) for your review.

The template creates a project based on the default ASP.NET 'single page application' with a Durandal 2.0.1 spa replacing the default spa. The new Durandal app is fully integrated with OWIN security and supports 3rd party authentication.

The template has been created from this project: https://github.com/Useful-Software-Solutions-Ltd/Durandal451.