Add label position for Data Store Reference

Fixes bpmn-miwg/bpmn-miwg-test-suite#203
Adds missing image for bpmn-miwg/bpmn-miwg-test-suite#195
Merge pull request #206 from camunda/c.1.0

Add label position for Data Store Reference
Fixes bpmn-miwg/bpmn-miwg-test-suite#203
Adds missing image for bpmn-miwg/bpmn-miwg-test-suite#195