- #439 (2 of 3)
- correct namespaces
- correct `Resources` class and member names; add new resources
- add `RequestServices` property to `ClientModelValidationContext`
- adjust to modern `IUrlHelper` API
- add `IClientModelValidator` support in `DataAnnotationsModelValidator`
- move previously-unused `StringSplit()` to `RemoteAttribute` and rename
- rewrite `RemoteAttributeTest`
- improve test method names
Reduce number of `[Remote]` constructor overloads
- remove `AreaReference` enum and related `[Remote]` constructor overload
- use `null` or empty `string` as explicit reference to the root area
- generally reduce parameter validation; match `UrlHelper`
Cleanup
- correct Engineering Guidelines violations
- especially: add doc comments
- correct spelling error in `_additonalFieldsSplit`
nits:
- minimize `null` checks in `AdditionalFields`
- make `GetClientValidationRules` `virtual`; some subclasses use `new` today
- add tests of `DataAnnotationsModelValidator.GetClientValidationRules()`
- remove `builder.ToString()` calls since it appears
https://roslyn.codeplex.com/workitem/246 has been resolved or Moq has
worked around that issue.
