* Remove output port and convert method. Add a method call in process tuple which takes each tuple as an argument. Default implementation does nothing. If the user wants to output something they can add an output port when they implement the abstract class.
   * Add close file method to AbstractFSWriter
   * add rotated file hook
   * make methods for FSWindowWriter non final
   * Changed rotate function from private to protected.
   * Removed unecessary close file and simplified name.
added some explanatory comments to FSWriter
Merge branch 'ilooner-MLHR-1581_pull' into dt-dev