This week's copyright, media and entertainment law updates are as below:   Songwriters signed away their right to sue for "Shake It Off" Taylor Swift provided sworn testimony in one of the several copyright infringement litigations she has been involved in over "Shake It Off" in August. The Artist’s lawyers now claim that the plaintiffs waived their right to sue when they signed publication contracts years ago. Taylor Swift stated, among other things, that she "had never heard the song Playas Gon'…