This change adds a [Required] client validator when
ModelMetadata.IsRequired == true. The bulk of the changes here are
mechanical updates to test files.
Also ensures that when a type is marked as skipped, any sub property which is model bound (and hence a modelstate un validated entry),
is marked as skipped (otherwise it would cause the ModelState to be invalid).
Also fixing a bug in model state dictionary FindKeyWithPrefix was not considering [0] & [0][0] as a valid prefix.
Ryan Nowak
Harsh Gupta
N. Taylor Mullen