Correct format used when Html5DateRenderingMode==RFC3339
- http://aspnetwebstack.codeplex.com/workitem/479
- "EditorFor Date Value Does Not Output Correct Date Format As Per RFC 3339"
- Reported issue was a bug in HtmlHandler.Html5DateRenderingMode handling
- Code previously assumed any use of an edit format string indicated an
explicit [DisplayFormat] attribute
- Instead track whether edit format string came from [DataType] attribute
in new ModelMetadata.HasNonDefaultEditFormat property
- FxCop required me to refactor DataAnnotationsModelMetadataProvider slightly