0.8

• change from distutils to setuptools, easy installation using pip
• introduce gettext localisation, localise Mistkerl messages properly
• Mistkerl:
  • show correct formula sign for min/max mistkerl checker
  • accept a file name as input, too
• bug fix: recognise headings with non-letter characters as first character
• automatically deduplicate headings
  • slide shows might reuse heading texts multiple times subsequently, remove
    duplicates from table of contents; remove Mistkerl checker for this
    behaviour as well.
• correctly handle unnumbered headings
• remove format from the lecture configuration, because it is a property of the
  conversion itself, not of the lecture source
• allow page number ranges: || - page 9-11 -
• do not include "glossar.md", "kurz.md" and "index.md" in lecture material
  anymore, these can be put in "anhxx" (the appendix)