core-4352 remove option to dismiss threshold message manually.
CORE-4671: 
* Created new ErrorHandler which listens for resize events from its
given widget.
CORE-4671:
* More corrections to side error issue.
CORE-4671: Added KLUDGE annotations 
This is to track the changes related to this ticket, as they will have
to be revisited when we update GXT.
CORE-4646 Added a ContextualHelpToolButton.

Refactored the help ToolButton from IPlantDialog into a ContextualHelpToolButton class.
Removed the logic for hiding the popup in ContextualHelpToolButton, since the auto-hide setting in ContextualHelpPopup hides the popup before the tool button can be clicked a second time.
CORE-4691 Added ImportUrlValidator.

Renamed UrlValidator to ImportUrlValidator for use only in the "Import from URL" form.
Re-added a UrlValidator with less restrictions.
CORE-4685 Refactored Max/Min Number Validators.

Renamed the Min/MaxDoubleValidator to DoubleAbove/BelowValidator.
Renamed the Min/MaxIntegerValidator to IntAbove/BelowValidator.
Changed the logic of these Validators to validate their given values exclusive of their limits. For example, IntAboveValidator will validate that the given value is greater than its limit, instead of greater than or equal to its limit, which is the default behavior of GXT's MinNumberValidator.
Updated the validation message in NumberRangeValidator.
Removed CommonUiValidationMessages.

This class is duplicated by IplantValidationMessages in ui-resources-module.
Removed obsolete I18N class.
I18N#RULES in ui-resources-module was renamed to VALIDATION.
Refactored all references to the old I18N#VALIDATION to use the same one in ui-resources-module instead.
Merge branch 'master' into STABLE