Moved infix set operators from expressionTerm to expression production rule.
Moved infix set operators from expressionTerm to expression production rule.

MeasureAuthoringTool/clinical_quality_language,cqframework/clinical_quality_language,MeasureAuthoringTool/clinical_quality_language,cqframework/clinical_quality_language,wanghaisheng/clinical_quality_language-Research,wanghaisheng/clinical_quality_language-Research,DBCG/cql_engine,MeasureAuthoringTool/clinical_quality_language,wanghaisheng/clinical_quality_language-Research,DBCG/cql_engine,MeasureAuthoringTool/clinical_quality_language