updating the page generator and base view to work with razor helper functions

@NTaylorMullen 
You don't currently use this property in your `WriteAttribute` methods, therefore your attribute may be improperly encoded. We do this in MVC here: 
https://github.com/aspnet/Mvc/blob/dev/src/Microsoft.AspNet.Mvc.Razor/RazorPage.cs#L368-L383