def revert(file_path='')
      if file_path.empty? then file_path = self.svn_repo_working_copy end
      svn_session() { |svn| svn.revert(file_path) }
    end
def revert(file_path='')
      if file_path.empty? then file_path = self.svn_repo_working_copy end
      svn_session() { |svn| svn.revert(file_path) }
    end
discard working copy changes, get current repository entry