Fix for #1448 - ViewComponents must be public top-level classes

ViewComponents and Controllers now follow the same rules exactly for what
types of classes they can be.

Also corrected a bug in a test for controllers. Closed-generic types can
be controllers, the test was wrong.
TODO removal part 1 - ActionExecutorTests
Fix for #1442 - Find better names for ApiExplorerProperties

Taking the suggestion here to move these to a sub-object. This is future
proof in the event that we need to capture more data for ApiExplorer, and
reads better.
Added a functional test for view precompilation
Revert "Added a functional test for view precompilation"

This reverts commit 310feeb826b3a5ea489925ca83628e96f8af5817.
Update to JSON.Net 6.0.6

Fixes #1473
Merge branch 'release' into dev
Added description in project.json for all projects
Merge branch 'release' into dev
Fix for #1052 - ViewComponents should support fully qualified names

This change adds the concept of a full-name to viewcomponents. View
components can be invoked using either the short name or long name. If the
provided string contains a '.' character, then it will be compared against
full names, otherwise it will be matched against short names only.

The short name is used for view lookups.

If the name is explicitly set via ViewComponent attribute, then the full
name is the name provided. The short name is the portion of the name after
the last '.'. If there are no dots, then the short name and full name are
the same.

If the name is not set explicitly, then it is inferred from the Type and
namespace name. The short name is the Type name, minus the 'ViewComponent'
suffix (if present). The full name is the namespace of the defining class,
plus the short name.
Rework `ViewDataDictionary` constructors to ensure `ModelMetadata` is never `null`
- `ViewDataDictionary<TModel>` constructors now pass `typeof(TModel)` to base
  `protected` constructors
 - move type compatibility checks into base `ViewDataDictionary`
 - remove `ViewDataDictionary<TModel>.ModelMetadata` override
- don't retrieve `ModelMetadata` twice in a single constructor invocation
- remove newly-unused `protected` properties and use `private` fields in copy
  constructors

Address longstanding problems found (see #1466)
- avoid reusing `ModelMetadata` after `Model` value changes
 - reset `ModelMetadata` backing field in `Model` setter
 - `Model` and `ModelMetadata.Model` could previously get out of sync
- carry `ModelMetadata` forward from an outer scope only if `Model` matches
 - previously two scopes could have different `Model` values but share their
   `ModelMetadata` (and `ModelMetadata.Model`)
 - related to previous item but didn't require `Model` setting; switching
   to a property of the same type as containing `Model` was enough
- avoid NRE if `ViewDataDictionary<int>.Model` is read before it's written
 - problem affected all non-`Nullable` value types
- `ViewDataDictionary.ModelMetadata` setter should throw if value is `null`

nits:
- add and reword doc and code comments
 - `ViewDataDictionary<TModel>` constructors should only inherit base's
   parameter descriptions; have more information in the derived class
- make a few `ViewDataDictionary` properties get-only
- clean up `using` statements in `ViewDataDictionary<TModel>`
- make two constructors `internal`
Correct some `ViewDataDictionary` constructor calls
- ensure correct `ViewData.ModelState` value in a `RazorPage` instance
- let view components inherit `ViewData.Model` from surrounding context
- do not create an isolated `ViewDataDictionary<TModel>` in one HTML helper
 - allows previous `ViewDataDictionary<TModel>` constructor to be `internal`
  - also add comments for that constructor
- change two `ViewDataDictionary` copy constructor calls to avoid uselessly
  copying `Model` and related information from source
Correct code checking for `ViewDataDictionary.ModelMetadata==null`
- `null` checks can generally be removed but in one case needed to
  special-case metadata for `object`

nit: remove duplicate empty `string` check in
`ExpressionMetadataProvider.FromStringExpression()`
Adjust tests to handle new `ViewDataDictionary` invariants
- ensure `ViewDataDictionary` constructors are not passed a `null` or
  `Mock.Of<IModelMetadataProvider>()` instance
 - `ViewDataDictionary` constructors always use the `IModelMetadataProvider`
- `viewData.ModelMetadata` now never `null`
- `ViewDataDictionary<int>.Model` no longer throws if read before it's written
- `ViewDataDictionary.ModelMetadata` now copied to new instances in fewer cases
 - e.g. don't use unusual `object` datatype with customized `ModelMetadata`
More `ViewDataDictionary` tests
- separate and extend `ViewDataDictionary<TModel>` tests
Revert "Revert "Added a functional test for view precompilation""

This reverts commit 6b2ab32885a526bbfacbd7ff2aa7cdcc8e4cde5f.
Adding functional tests for Filters.
Fix #1370 - Always use the provided formatter in JsonResult

The change here is to always use the provided formatter, instead of using
it as a fallback. This is much less surprising for users.

There are some other subtle changes here and cleanup of the tests, as well
as documentation additions.

The primary change is that we still want to run 'select' on a formatter
even if it's the only one. This allows us to choose a content type based
on the accept header.

In the case of a user-provided formatter, we'll try to honor the best
possible combination of Accept and specified ContentTypes (specified
ContentTypes win if there's a conflict). If nothing works, we'll still run
the user-provided formatter and let it decide what to do.

In the case of the default (formatters from options) we do conneg, and if
there's a conflict, fall back to a global (from services)
JsonOutputFormatter - we let it decide what to do.

This should leave us with a defined and tested behavior for all cases.
Fix for breaking API change from routing
Follow up to JsonResult changes

Changing the WebAPI shim to use the new and improved JsonResult.