handle redundant column/field names

[RobLBaker]

Sometimes people will re-use the same column or field name across multiple data files (e.g. "scientificName"). Right now the summary tables assume that all column names are unique across all data files in a data package. This probably needs to be updated/fixed likely this will require:

1. more user input?
2. updating the relevant functions, not just the DRR template.