[rules-dev] Rule Flow

There is a working Rule Flow implementation in drools-core now (not in drools-compiler and the the drl language yet). It works in a similar manner to activation groups. Each rule can be a in a RuleFlowGroup when that rule activates instead of being added to the Agenda it is instead added to the RuleFlowGroup it sits there till it is either de-activated or the RuleFlowGroup itself is activated. When the RuleFlowGroup is activated it adds all activations to their respective AgendaGroups, when all those rules are fired the RuleFlowGroup activates all child RuleFlowGroups. See the unit test AgendaTest for how it works. So currently it does branching but joins still need to be done and possibly allowing multiple flows for the same ruleflow network. I have removed MVEL from core, so MVEL related tests ('from') aren't working at the moment. As soon as the jdk1.4 version is working with MVEL I'll fix that up. Mark