Kat Walker has an appealing burr in voice when she hits lower notes, and her easygoing style is charming for its lack of pretension. But when an album covers the standard-est of standards, the versions need to open up some aspect of the song or feature astounding musicianship. The playing on Jazz Skat Gumbo is fine, but really, neither happens, so it’s hard to think of the album as more than a souvenir to sell off the bandstand. Seriously, is there another reason to record “It Don’t Mean a Thing,” “Cry Me a River,” “Fever,” “Mack the Knife, “Me and Bobbie McGee,” Ain’t Misbehavin’” and “Over the Rainbow” in 2009?