Added tool tips to homepage icons CORE-4370

https://pods.iplantcollaborative.org/jira/browse/CORE-4370
core-4370 add tooltip for desktop icons.
core-4371 fix menu button text
core-4301 msg for unique kb shortcuts
core-4301 msg for duplicate shortcut key
# WARNING: head commit changed in the meantime

IN PROGRESS - issue CORE-4296: The DE needs to have a window for viewing
system messages. 
https://pods.iplantcollaborative.org/jira/browse/CORE-4296

externalized system messages messages and errors
improved styling for announcer.
IN PROGRESS - issue CORE-4296: The DE needs to have a window for viewing
system messages. 
https://pods.iplantcollaborative.org/jira/browse/CORE-4296

Moved system messages resources to the ui-resources project.
Merge branch 'master' of https://github.com/iPlantCollaborativeOpenSource/ui-resources-module
Merge branch 'master' into STABLE