Scheduler

It's a half done pull request, need some feedback to improvement the code. It's aim to schedule the user configured task resource requests.
Mainly done: 
1. move the package into cluster
2. package workerInfo( Todo: using host:port)
3. parse the configuration into task arrangement


in scala, there is UAP rule(uniform access principal)

It means we don't need to(also don't want to) know whether it is a field or method.