Merge pull request #42 from greenTara/master

fixing negation approach
Merge pull request #44 from greenTara/master

fixing negation approach
corrected the @per attribute in expressions, so that it includes the "effect" value.
corrected the @per attribute in expressions, so that it includes the "effect" value.
Merge branch 'master' of https://github.com/RuleML/reaction-ruleml
added @per="effect" to Expr and Fun
Merge pull request #45 from greenTara/master

Re issues #4 #36 #41 #43