swagger plugin does not accept multiple keys

[rvilalta]

Example: list costCharacteristic {

            key 'costName costValue costAlgorithm';

            config false;

            min-elements 1;

            uses CostCharacteristic;

            description "The list of costs where each cost relates to some aspect of the TopologicalEntity.";

        }

The key in swagger should be a combination of the three keys.

Proposed solution: create a key, which replaces the spaces with _