introduced issue-list (artifact)
Merge branch 'master' of https://github.com/aim42/aim42

# By GernotStarke@iMac
# Via GernotStarke@iMac
* 'master' of https://github.com/aim42/aim42:
  updated domain model - we now talk about "issues" instead of problems...
  * next iteration in removing "problem"...
  first version of domain-model in OmniGraffle