A “copyright troll” that files lawsuits of “questionable merit” in order to extract settlements from the defendants failed to make a case of copyright infringement against a residential real estate development company, a federal appeals court held.The 7th U.S. Circuit Court of Appeals on Friday declined to revive Design Basics’ lawsuit accusing Signature Construction Inc. of infringing 10 copyrighted floor plans for suburban single-family homes.The Design Basics plans are made up largely of standard elements in the genre …