title: Check to See if File is in Repository with SharpSVN
body: <p>How do I check if a file is already in a repository (or NOT in the repository) so I can determine whether I need to 'add' it first before doing the check in?  (For the record, I have check-in working, but I get an exception when I try to check in a file that has not yet been added to the repository.)</p>