Disallow Elements and Attributes with the Same Uncased Name

[TomCarlson-NTAC]

New NDR rule. Casing will be different due to current rules, but do not allow elements and attributes in the same namespace to have the same name. This causes problems in case-insensitive environments.

Dr. Scott: Same uncased name. Is there a rule between elements in the same namespace?

#todo Christina and Tom Carlson draft a rule for this.

[cdmgtri]

Migrated to niemopen/niem-naming-design-rules#11