IN PROGRESS - issue CORE-4152: Implement App Integration WYSIWYG Pallete
Drag n' Drop 
https://pods.iplantcollaborative.org/jira/browse/CORE-4152

Improved drag source application in AppIntegrationPalette. 
Added a drag start handler to the argument group drag source in
AppsIntegrationViewImpl which collapses all argument groups.