Wrote drafts of key interfaces and single worker processing code

Interfaces Drafted:
DataSet - Data interface to point to an in memory data store
Folder   - Function  (S,X) -> S to model fold operation
Mapper - Function A -> B to model map operation
Token  - The code/state passed from server to server

Classes:
ControllerNode - Main class for controller nodes
WorkerNode - Main class for worker nodes
Worker - Class which iterates through local data set and updates token