Define functional relation between Job and worker

[zephyr1999]

Worker should manage:

• input and output of data
• model training with job
• classification with job
• other functions as needed (training cycles, ect)

And Job should provide functions:

• training(**kwargs) where kwargs is a dictionary of named arguments and values
• run classifier(iterator, stop_condition) where the iterator is "live", i.e. can be modified and added to while its being iterated over. It should be message objects and stop condition can be changed in real time by the worker. This should return another iterator of classified message objects.