Description of problem:
After saving a BP which has a TextAnnotation or Group inside a Swimlane, the TextAnnotation or Group is no longer contained in the Swimlane. In the editor when you move the swimlane, the TextAnnotation or Group does not move with the swimlane, but stays where it is.

Note: With the eclipse bpmn2 api, a swimlane can only contain elements of type FlowElement. TextAnnotations and Groups are Artifacts, which within the api are not flowElements.
The BPMN2.0 spec does not allow  artifacts to be placed inside container nodes, so we will need to extend our implementation of the BPMN2.0 spec (and the Eclipse bpmn2 api) so that TextAnnotations and Groups within swimlanes behave correctly in jBPM Designer.

See attached video.

Version-Release number of selected component (if applicable):
BPMSuite 6.1.0

How reproducible:
Happens in all browsers, but in IE10 and IE11, the problem is worse because each time you drag-drop an item, e.g. a TextAnnotation, the whole BP is saved to JSON then reloaded, to workaround a bug in IE's handling of SVG markers.

Steps to Reproduce:
1. Create a new BP
2. Add a swimlane
3. Add an activity, e.g. a Start activity inside the swimlane
4. Click the buton on the Activity to add a Text Annotation 
5. Move the swimlane. At this point, the Annotation moves with the swimlane because it's inside it in the metadata.
6. Save the BP (and optionally close and re-open it)
7. Move the swimlane. Now the Annotation stays where it is while the swimlane is moved.


Expected results:


Additional info: