In their new rock musical "Billy and the Killers," lyricist/librettist Jim Shankman and composer Peter Stopschinski channel Nicholas Ray, David Lynch, Elvis Presley, and Dashiell Hammett to concoct a muddled tale of teenage rebellion that dead-ends in an even less coherent murder trial. Along the way, there are some well-performed songs whose lyrics seem to be tied to the plot, but it's often hard to tell, since, as …