Tidy up command arg handling a bit
Make multiline end output same width as start
fold selection in attelo learn/decode

Optional ability to select a single fold to learn/decode from.
This sits in a general arc of breaking up the monolithic evaluation
process into smaller self-contained (and more distributable) parts.
Tidy up attelo learn imports
Tidy up attelo decode

pylint, pep8, and nicer arg validation
kill dead code: args.config now required
pylint attelo.args
Rename attelo.features.Features to .Phrasebook

Calling this thing Features is a bit silly because it does not
so much consist of a list of features as their names.

Meta features is not great because not all of the features are
of meta type
Move perceptron model name out of decoder control

Minor layering refactor
attelo.table: trivial refactor
attelo.table create/move select_edu_pair helper

This was carved out of some of the scoring code.
Refactor decoder control

- Use DataModel tuple to pack data and associated model
  into single arg

- Remove decoder from decoder config (more reusable)
Overhaul scoring; add attelo decode --score

- Clean up code
- Report attachment/labeling separately.
- attelo decode score can dump counts to be added up later
Remove redundant layer in json params output