Moved src/framework/mixer/mixer.hpp from develop branch.
Moved src/framework/mixer/mixer.hpp from develop branch.

gintenlabo/jubatus_core,Asuka52/jubatus,roselleebarle04/jubatus,rimms/jubatus_core,kumagi/jubatus_core,jubatus/jubatus,roselleebarle04/jubatus,mathn/jubatus,kumagi/jubatus_core,elkingtonmcb/jubatus,Asuka52/jubatus,rimms/jubatus_core,rimms/jubatus,gintenlabo/jubatus,gintenlabo/jubatus_core,rimms/jubatus_core,jubatus/jubatus,gintenlabo/jubatus_core,gintenlabo/jubatus,kmaehashi/jubatus,jubatus/jubatus,mathn/jubatus,kmaehashi/jubatus_core,elkingtonmcb/jubatus,rimms/jubatus,kmaehashi/jubatus_core,rimms/jubatus_core,kumagi/jubatus_core,gintenlabo/jubatus_core,kumagi/jubatus_core,kmaehashi/jubatus_core,kmaehashi/jubatus_core,kmaehashi/jubatus