Issue #501 - Add argument to NewField to set error class for field.
Issue #501 - Update calls to NewFIeld in samples.
Issue #501 - Remove errorClass argument added to NewField. Check whether ERROR_CLASS is set in renderArgs to override default ERROR_CLASS.
Issue #501 - Override ERROR_CLASS in validation Sample 4 as a test case.
Merge pull request #511 from davidzchen/error-class

Make Field Error Class for a Field settable (#511)