store source data lists in a format other than csv?

[smnorris]

Editing the data list in Excel is handy, and it is nice that GH autoformats the csv.

However:

• evaluating diffs from files edited in Excel is a pain because all lines are changed, Excel defaults to windows line endings and automagically converts every line
• just reading the data list in a text editor is very awkward because of the long list of columns, it really has to be edited a spreadsheet tool

Not sure if this is enough to warrant moving from csv. I think the process_order may no longer be required in the list - if that is the case, simply removing that column may be enough (it will make diffs much easier to visualize because only the line associated with a given source will change, just have to remember to reset line endings on commit after edits in Excel)