Merge pull request #12 from bpmn-miwg/master

update from MIWG
Merge pull request #13 from bpmn-miwg/master

Merge updates from original
Added roundtrip tests for Yaoqiang 2.2.3
Added export test results for YaoQiang 2.2.3
Added export test results for YaoQiang 2.2.2 part 2, updated Excel sheet
Updated roundtrip tests for camunda Modeler 2.0.12
Updated roundtrip tests for eclipse BPMN2 Modeler 0.2.6
Merge pull request #109 from mskurz/master

Added roundtrip tests for Yaoqiang 2.2.3, camunda Modeler 2.0.12, eclipse BPMN2 Modeler 0.2.6