* some experiments with new list-style for pattern index
* see asciidoc-help for suggestion (will do tomorrow)
added list-punctuation for assertions
New pattern: Use Invariants to Kill Zombies (issue #34)
  Completed work on this specific use of invariants
  Also added some bibliography along the way
  and corrected a small typo in the pattern index (missing dot before assertions)
Merge branch 'gernots' into invariants_and_zombies