Add v1.5.11 to CHANGELOG
Add v1.5.11 to CHANGELOG
mickdwyer/Hystrix,mattrjacobs/Hystrix,ianynchen/Hystrix,justinjose28/Hystrix,mattrjacobs/Hystrix,mattrjacobs/Hystrix,mickdwyer/Hystrix,Netflix/Hystrix,justinjose28/Hystrix,eunmin/Hystrix,justinjose28/Hystrix,eunmin/Hystrix,mickdwyer/Hystrix,eunmin/Hystrix