fixed some tags
first commit

added taggedpipeline.py
which incorporates our xml style annotations into the pipeline
added supervised_learner2.py

made new version 2 of supervised_learner.py
which uses the new taggedpipeline.py to process the tags
main advantages are:
- one pass through text when processing; maintains separation of
'hidden' features (including tagging data), and 'visible' features,
which are generated by the templating function
- maintains sentence and word tokenization with tag tokenization

will keep as v2 until has been debugged, then can switch to main v