Issue Description

Both the read_coverages and read_lossfactors functions wrongly try to search for if an input file exists before attempting to read any data, even if using the use_stdin argument.

Steps to Reproduce (Bugs only)

Running the following examples, especially when not in the same directory as the input files, or when the input files do not have the default filename result in the FileNotFoundError

bintocsv coverages < path/to/input/nonStandardCoveragesName.bin > output.csv
bintocsv lossfactors < path/to/input/nonStandardLossFactorsName.bin > output.csv
csvtobin lossfactors < path/to/input/nonStandardLossFactorsName.csv > output.bin

Version / Environment information

Example data / logs