Add the `rake clean` task
Add the `rake clean` task

hkuplg/fcore,xnning/fcore,zhiyuanshi/fcore,bixuanzju/fcore,zhiyuanshi/fcore,hkuplg/fcore,bixuanzju/fcore,hkuplg/fcore,xnning/fcore,wxzh/fcore,wxzh/fcore,wxzh/fcore,bixuanzju/fcore,zhiyuanshi/fcore,xnning/fcore