Add transient state

[mustangJaro]

This adds a new :transient? key to the rule structure to allow users to be able to identify which rules can be run more than once. This can be helpful for SPAs where I want to load new state every time a certain condition is met, for example, going to a specific URL should reload certain state.

Specifically, this restricts the app from storing the "transient" rule in rules-fired so that async-flow doesn't track the execution of it in the same way. However, the dispatch events are still executed as normal.