Black Crowes fans may be feeling some sting from the group’s latest break-up, but frontman Chris Robinson has a musical salve. The Chris Robinson Brotherhood, which the elder Robinson started in 2011, is the singer’s extension of the multisourced, open-ended musicality that’s part of the Crowes sound but even more fully embraces the Grateful Dead/jam band spirit of anything goes and no song being finished until the musicians decide it’s run its course.