Handle file names with both upper and lower case in names

[rdrclrbh]

right now iVABS seems to only like files with all characters with upper case letters. It should be able to take files with either upper or lower case names. e.g., files that we tried to run with this had names like a094r8m3.dat and a094r8m4.dat. We could get iVABS to read this in only when we changed the letters to upper case.