Add human-readable stringification method to Identifier class

[nolanwelch]

Description

The current Identifier class's __str__() overload generates a stringification that is appropriate for filename use. However, in some cases (for example, log generation) it is beneficial to convert the Identifier object into a string containing information that is beneficial to humans (for example, whether the identifier's variable is a part of a combination row in the data dictionary).

• Keep current implementation of __str__, and add new stringification (as used to generate file names) should be broken out into a different class method.
• Q: What information should be included in the human-readable stringification? If we dip into checking whether the variable is part of a combination row, what its datatype is, etc., we'd need access to the data dictionary. That makes me feel like this is something that should be recorded at object initialization...

[nolanwelch]

Resolved by 63a685392e46f4364b637dfd6a2ac86894f91838.