Added AbstractElementEvent to provide common data for events with elements.
Added SetEvent and SetListener so that extensions can register a hook for Set commands.
Merge branch 'master' of https://github.com/concordion/concordion
Merge pull request #96 from johnbhurst/master

Added SetEvent and SetListener so that extensions can register a hook for Set commands.
Updated reference specs to use concordion:run. Cherry picked dkatzel-home/concordion@d78e277.
Modification so "starting fixture" line is not printed if we are getting results from the cache.