[tei2folia] Convert w@norm, w@join, fix list handling and various conversion problems

[proycon]

Some issues arose trying to convert a TEI document to FoLiA: http://www.deutschestextarchiv.de/book/show/wolff_anfangsgruende01_1710

There a lot of elements that can not be converted:

• [tei2folia WARNING] Unhandled tag in structure context: s (in p) (I wonder what triggers this because this seems rather basi
• [tei2folia WARNING] Unhandled tag in structure context: fw (in div) (we don't handle fw yet)
• [tei2folia WARNING] Unknown tag in structure context: s (in item) (list processing seems to go wrong)

It seems this document diverges from the TEI collections we were used to hitherto.

In addition, there are interesting extra attributes in this document that should be converted, such as norm and join (on w)

[proycon]

This TEI dialect is documented here: http://www.deutschestextarchiv.de/doku/basisformat/