test and fix TEI Workflow

[sgfroerer]

Make the TEI Workflow work (and flow) with the example publication.
Document the result in README.

Requirements:

• Outcome should be the same as in the eoaTeX workflow (unless for small exceptions and for good reasons) for the following products:

  • eoatex
  • PDF
  • imxml (django, epub are created from it)

[sgfroerer]

Would also be nice to provide a "one script does it all" process_tei, analogous to the src/process_eoa_latex.py script.