Create a "transaction"-like context for WMA to prevent inconsistent intermediate-states

Create a "transaction"-like context for all WMA to prevent inconsistent states during propagation. The idea is to delay agenda changes (rule activations, cancellations and re-activations) until the whole propagation is finished. This is to avoid inconsistent states when the same fact is propagated through multiple RETE branches.

Examples of cases that require this include:

• forall re-activating on fact retractions
• fireUntilHalt immediately firing rules that are activated and canceled during the same WMA