The London jazz festival is the seasonal highlight, but Hugh Masekela, Larry Willis and a full performance of Bright Phoebus are nothing to sneeze at eitherLondon jazz festivalThe singer, composer and bassist Esperanza Spalding has broken out of the jazz loop with more pop-oriented music, but she comes to the 2013 LJF as a virtuoso double bassist, part of a trio with the pianist Geri Allen and drummer Terri Lyne Carr…