Replaced GXT 2.2.5 MessageBox usage with new iPlant equivalents.
Merge branch 'gxt3-sandbox' of https://github.com/iPlantCollaborativeOpenSource/ui-pipelines-module into gxt3-sandbox

Conflicts only affected imports.

Conflicts:
	src/main/java/org/iplantc/core/client/pipelines/views/panels/PipelineEditorPanel.java