Feature request: Add file to attributes

[maia-sh]

It would be great to be able to distinguish the source of each attribute, i.e., which file does each variable come from? This is already captured in attributes.csv under fileName. Would it be possible to integrate this into dataspice.json and the resulting HTML webpage? For example, using your https://github.com/amoeba/dataspice-example:

The Attributes table on the HTML would have an additional column specifying File for each Name. E.g.,
Stock.ID appears in StockInfo.csv, BroodTables.csv, and SourceInfo.csv
Species appears in StockInfo.csv
Etc.