Accommodate API change from PLFM-2091

Changed addEvaluationParticipant to joinEvaluation.
Programmatically joining an Evaluation is now sort of convoluted.
SYNR-566 and SYNR-567

- Added allowParticipation() to give arbitrary users permission to submit to an Evaluation.
User group participation

+ Added ability to search for and give Read/Participate rights for user groups in an evaluation
Merge pull request #91 from kaysoky/evalAPI_change

Eval api change