changed KnowledgeBase.getVariable(String) to return null if not found
Merge branch 'master' of https://hellsync@github.com/BerndBrinkmann/ExpertShell.git
added Rule.getUncertaintyMethod()
sussing out where UncertaintyManagement etc are stored
Merge remote-tracking branch 'origin/master' into master1
fixed certainty factor values in test case