Processor api

Sweetheart S2,

Follow in the MR the check-pointable processors.

With this MR it contains:

• Base Processor class that defines methods for fit a processor given some samples (optionally) and to transform samples
• ProcessorPipeline that:
  • stack those Processors sequentially
  • checkpoint them if necessary
  • fit processor if they are fittable
  • transform them

Close #4 (closed)

ping @andre.anjos @amohammadi