fmudesign: using file input from RMS seeds

[tommyod]

Comment from Helena:

I tried (not too hard) and failed to use the 3rd option "filename for file" in rms-seeds. I think I tried to add a .txt file on the same folder as the design matrix. Maybe some additional explanation on how to use it would suffice, or maybe it is not working as intended. If the scope of your work could include to check it more in detail, that is one suggestion.