Resolve confusion on x/y and array row/column

[svank]

CoordinateIdentifier is defined as storing x and y coordinates. After star identification, a bunch of CoordinateIdentifers are instantiated, with sep's x going into the y slot and vice-versa, so the x/y slots of CoordinateIdentifer are really being used as row/column slots. And indeed, when making the stellar cutouts, x is used for the vertical axis and y the horizontal axis.

I'm not sure what the ultimate goal is for CoordinateIdentifer, but I think either its fields should be renamed as row/column or similar, or the x and y fields should be used consistently as vertical and horizontal coordinates. (This bit me while visualizing my patches.)

[jmbhughes]

I've waffled back and forth between whether to use a namedTuple with the CoordinateIdentifier versus just a regular tuple without named fields. Did you have a preference or an alternative suggestion?

You're right that we should clarify the convention and be consistent though. I'm fine with making it row and col.

[svank]

One upside to using the namedTuple is that one doesn't have to memorize/look up the order of the elements in the tuple, and it cuts down on the use of magic numbers (e.g. xs = [k['x'] for k in cpc.keys()] vs. xs = [k[2] for k in cpc.keys()])

Changing the names to "row" and "col" might indeed be the easiest fix here.