Created an Image Provider for Custom Tasks that registers images in
extension plugin resources.

Added "propertyTabs" and "icon" to <customTask> extension. The "icon"
uses the above Image Provider for toolpalette and to decorate figures on
the canvas.

Reworked Custom Task Property tabs and Feature Containers to use the
above Image Provider.

Use the "description" field from <customTask> for the text in
"Description" property tab.

Default Detail Composite now searches ExtensionValues for properties to
render.

Moved the EMF Resource load and save options from Model Resource Factory
to ResourceImpl to avoid confusion.

Fixed Bpmn2ModelerResourceSetImpl so that it picks up the correct Model
Resource Factory depending on target runtime set for the project
containing the resource.
Fix "Diagram" menu contribution handler broken by juno API change.
Fix CallActivity, CallChoreography and CallConversation selection
combos. Creating a new target now adds a new BPMNDiagram for the
Activity.
Fix a bug in Import table. Enable Import object in default Target
Runtime.
Upversioned to 0.2.2
Update site Won't build unless wsil plugin version is specified explicitly
Fixed a bug in handling of "ref" references in customTask/property
extension