- #843
- add property as well as the related `[HiddenInput]` attribute
- use this property to address some TODOs in default display and editor templates
- no more `IHtmlHelper<object>` in `DefaultDisplayTemplates` and also no
need for `ViewDataDictionary<object>` in a few places
- mostly removals from `IHtmlHelper<TModel>` but did cleanup comments and
add `[NotNull]` for `DisplayFor()`, `DisplayNameFor()`,
`DisplayNameForInnerType()`, and `LabelFor()`
- also add `[NotNull]` for `this` and `Expression` parameters in some
extension methods
- first get old code in correct spot
- then get default templates working in new world
- usual things: `[NotNull]`, `var`, internal -> public
- provide a `HtmlHelper.GenerateOption()` static method
- pass an `ViewDataDictionary<object>` instance to `TemplateRenderer` constructor
- run default templates synchronously with an IHtmlHelper<object>
- copy over resources
- add Microsoft.Data.Entity reference for EntityState type
- use default templates in MVC sample
- remove most on-disk overrides of the default templates