Fix agent relationship bug. (#21)

Feature: Add relationships for target groups (#18)

* WIP: Add prisoners dilemma demo case. Update engine to support results return.

* WIP: Add relationships for target groups. Add improved error handling for llm.

* Add target group relationships.

* Fix agent converse feature. Update examples.

Bump version number.

Readme: Add examples.

Update package setup to include promp templates.