Add eye detection

[Eurybiadan]

Eye detection is currently meaningless- it checks for a column in the scaling file that isn't there.

Either add a bullet option to the GUI, or parse the filename looking for the eye.

[dontminchenit]

I looked into this.

Currently we're searching the .xls file for the identifier 'eye' in the first column and reads the associated 'OD' or 'OS' in the second column. This format is shown in the example examplePosition.xlsx in our demo.

I did find a bug with this though, which might explain any problems you've been having with using the eye information. Apparently we made a change to the parser a while back, such that all the values in the first column is converted to a number first, and then back into a string. This caused the identifier 'eye' to turn into a null, preventing it from being found. I've fixed this bug in my latest update by searching for the string identifiers like this, before converting the IDs.