pwmmatch.exact.r R4.1 update

[lindsaynhayes]

With the R updates the read.table needs to be more specified. This fixed it for me. If you want to future proof the scripts. same for the whitelist read.table command.

I've never done a pull request before so giving it to you this way. :)

if(exists('blacklist') & !is.null(blacklist)){
    blacktable=read.table(blacklist, header=FALSE, sep="\t", stringsAsFactors=FALSE, quote="")
}