Alert the user on error if including spaces in "--exportAttributes"

[tiagonmas]

Great tool. As feedback the tool could look at spaces, or alert the user as the following was shoing an error:

githubCsvTools -f doar2.csv -c -e -t ghp_TkQxXXXXXXXXXXXXXv6s2Gpbm1eX9yY -o myorgname -r myrepo --exportAttributes id, title, labels, comments, body

error: Error reading file.

I had to call with no spaces in the: --exportAttributes id,title,labels,comments,body

[gavinr]

PRs welcome for this.