logging for the view engine

initial ideas for the view engine. #1563
@avanderhoorn is there something in https://github.com/aspnet/Mvc/blob/dev/src/Microsoft.AspNet.Mvc.Core/ActionContext.cs that you want to see as part of the view engine logging? Looking at http://getglimpse.com/Docs/Views-Tab, I'm not sure what information would be appropriate for the "Details" column