Upgrade documentation site

Hi @AlphaGit and @matias78,

It seems that it is necessary to run documentation site in a clean environment without legacy versions of ASP.NET WebPages.

Probably it is also required to deploy the documentation in a clean server.

I have also tried to use a recent version of ASP.NET WebPages, but it did not work, probably because something change in the API breaking the backward compatibility because [RegisterVirtualPathFactory|http://msdn.microsoft.com/en-us/library/system.web.webpages.virtualpathfactorymanager.registervirtualpathfactory.aspx] "is not intended to be used directly from _your_ code".