slight speed-up in unicode/bytes indexing
slight speed-up in unicode/bytes indexing

dahebolangkuan/cython,mcanthony/cython,rguillebert/CythonCTypesBackend,fabianrost84/cython,encukou/cython,hpfem/cython,fperez/cython,acrispin/cython,scoder/cython,hhsprings/cython,fabianrost84/cython,c-blake/cython,cython/cython,mcanthony/cython,hhsprings/cython,mcanthony/cython,madjar/cython,hpfem/cython,larsmans/cython,andreasvc/cython,achernet/cython,cython/cython,da-woods/cython,hpfem/cython,ABcDexter/cython,mcanthony/cython,rguillebert/CythonCTypesBackend,ChristopherHogan/cython,marscher/cython,ChristopherHogan/cython,JelleZijlstra/cython,hpfem/cython,fabianrost84/cython,hhsprings/cython,scoder/cython,da-woods/cython,achernet/cython,roxyboy/cython,dahebolangkuan/cython,ABcDexter/cython,fperez/cython,encukou/cython,dahebolangkuan/cython,slonik-az/cython,madjar/cython,madjar/cython,achernet/cython,marscher/cython,acrispin/cython,slonik-az/cython,JelleZijlstra/cython,fperez/cython,achernet/cython,hickford/cython,rguillebert/CythonCTypesBackend,mrGeen/cython,cython/cython,hickford/cython,mrGeen/cython,JelleZijlstra/cython,fperez/cython,encukou/cython,hickford/cython,fabianrost84/cython,mcanthony/cython,bzzzz/cython,madjar/cython,hickford/cython,mrGeen/cython,dahebolangkuan/cython,c-blake/cython,bzzzz/cython,roxyboy/cython,andreasvc/cython,roxyboy/cython,encukou/cython,roxyboy/cython,da-woods/cython,acrispin/cython,slonik-az/cython,marscher/cython,ABcDexter/cython,rguillebert/CythonCTypesBackend,c-blake/cython,c-blake/cython,encukou/cython,slonik-az/cython,fabianrost84/cython,cython/cython,ABcDexter/cython,scoder/cython,c-blake/cython,hickford/cython,acrispin/cython,JelleZijlstra/cython,andreasvc/cython,mrGeen/cython,achernet/cython,roxyboy/cython,scoder/cython,marscher/cython,mrGeen/cython,da-woods/cython,ABcDexter/cython,dahebolangkuan/cython,hhsprings/cython,andreasvc/cython,hhsprings/cython,ChristopherHogan/cython,hpfem/cython,marscher/cython,larsmans/cython,slonik-az/cython,bzzzz/cython,larsmans/cython,JelleZijlstra/cython,larsmans/cython,bzzzz/cython,acrispin/cython,madjar/cython,larsmans/cython,fperez/cython,andreasvc/cython