A sports psychologist who maintains a former Chicago Cubs employee retweeted a passage from his book without attribution got the go-ahead Tuesday to pursue half the counts in his copyright-infringement lawsuit.In a written opinion, U.S. District Judge Robert M. Dow Jr. tossed two counts in Keith F. Bell’s lawsuit against Joshua Lifrak and the Chicago Cubs and allowed two others to go forward.Lifrak was the director of the Cubs’ mental skills program through the end of last season.Lifrak worked with the Cubs …