Improve de_DE providers

Compliance to PEP-8, PEP-263, and #125 draft coding guidelines.

This included sorting long lists of names and fitting them within 80-char lines. Note that for this I've used the non-locale specific `sort()` on the strings. Observe for example `countries` in `address.py` for de_DE which currently shows Österreich" as the last entry in that sorted order.