- 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
- correct file and class names for some HH extensions
- three class names were correct but didn't match containing file
- three class and file names matched but didn't start with HtmlHelper
- clean up trailing whitespace and long lines in changed Extensions.cs files
- `HtmlHelperPartialAsyncExtensions`, `HtmlHelperRenderPartialAsyncExtensions`
and `HtmlHelperValidationExtensions` lacked some `[NotNull]` attributes
- merge extension files by concept
- Display / DisplayFor / DisplayForModel methods all into `HtmlHelperDisplayExtensions`
- Partial / RenderPartial methods all into `HtmlHelperPartialExtensions`
- use `IHtmlHelper<TModel>` everywhere