IN PROGRESS - issue CORE-4126: Add system message display area to DE. 
https://pods.iplantcollaborative.org/jira/browse/CORE-4126

Changed the Header Menu Style to use AnchorDefaultResources.Style as its
interface.
Merge branch 'master' of
https://github.com/iPlantCollaborativeOpenSource/de-webapp into
gxt3-sandbox