added spec for identifier & actor
made new tests for Actor & Identifier pass
added an num_executed counter to the Actor
updated the spec for the config class
updated the spec for the action class
implmented the spec to support defining identifiers in the config, but not yet using them
the executed counters can now be counted up for every actor at once or just for one actor
added comment to config
updated README.md
bump to version 0.2.0