Fixing build break due to tests
Add `HideSurroundingHtml` property to `ModelMetadata`
- #843
- add property as well as the related `[HiddenInput]` attribute
- use this property to address some TODOs in default display and editor templates
Address TODO item in default `object` editor template
- add validation elements per property in this template
- update editor template test to expect new `<span>` in result
Do not repeatedly evaluate `ModelMetadata.Properties` enumeration
- supports useful property updates of `ModelMetadata` instances in the collection
- provide a controllable ordering using the `Order` value
- part of #964
Add `[HiddenInput]`, `ModelMetadata.HideSurroundingHtml`, and `.Properties` tests

nits:
- add a few missing default `ModelMetadata` property value checks
- cleanup some redundancies in test data initializers
Changes to enable XML Output Formatters.
- Unit / Functional tests for the same.
JsonResult to use ObjectResult for content negotiation to pick default json formatter.
Implementing ILoggerFactory.AddProvider
Fixing sample
Adding Input Formatters to MVC Options and using HeaderValueAbstractions
Reacting to System.IO.FileSystem package version change
Adding support for inheriting chunks from _ViewStarts as part of host
parsing.

Fixes #881
Replacing ChunkMergerBase with IChunkMerger
* Addressing PR comments and adding unit tests
Adding unit tests for IChunkMerger