Add gs-collections rich collections library as a compile dependency.
Tweaks to ForEach action to use gs-collections for iteration, removed unused CTOR parameter.
Tweaks to event router implementations to get maximum efficiency.
Rewrite CachingRegistry to use the gs-collections rich collections library. Addresses #297 by adding a configuration knob for setting a "consumer not found" handler if no consumers were found for a given notification key.
Merge pull request #313 from reactor/enhancement-consumer-registry

Enhance consumer registry