Add Excel (maybe aother attachments types) creates duplicate Loader ID's

[converseKarl]

1. Add Excel file to loader
2. Query loaders
3. Add same Excel file to loader (repeat process)
4. Query loaders

In v0.77, two entires Duplicate ID's

I would expect it would at the very least to create a new different Loader ID or if its able to determine the spreadsheet is same as before (filename matched) it will not add it and return a "could not add, as named resource already exists"