Initial integration of PipelineCreator.

Added a PipelineBuilderPanel that contains the App categories, listing grid, and the PipelineCreator in a BorderLayout, with drag-n-drop listeners that allow apps to be dragged from the grid and appended into the PipelineCreator.
Removed the Mapping button from the PipelineEditorPanel and replaced the "Select & Order" panel with the new PipelineBuilderPanel.
Updated PipelineBuilderPanel to use new PipelineCreator::appendApp method.
Updated JSON methods in PipelineBuilderPanel.

Updated PipelineBuilderPanel::toJson to simply return the PipelineCreator::getPipelineJson object, and PipelineBuilderPanel::setData to expect this JSON.
Added a PipelineBuilderPanel::getPublishJson that converts the PipelineCreator JSON to a format expected by the publishWorkflow service call.
Updated the PipelineDNDListener::dragDrop method to pass the template ID of the app into the PipelineCreator.
Updated PipelineEditorPanel to use the unconverted JSON from PipelineBuilderPanel for its toJson and configure methods (for saving and restoring state).
Addded PipelineEditorPanel::getPublishJson that builds all the required JSON for the publishWorkflow service call.
Updated PipelineBuilderPanel::validateDNDEventApps.

This method no longer checks if the event is cancelled, since it may be cancelled by the DNDManager, but the status will still need to be updated by the listener.
Removed Buttons and CardPanel from PipelineEditorPanel.

The PipelineInfoPanel is now in the East region of this panel, next to the PipelineBuilderPanel.
Removed the PipelineStepValidationEventHandler from PipelineEditorPanel, since PipelineBuilderPanel can't listen to the PipelineCreator's events and emit its own PipelineStepValidationEvent.
Updated the Publish button so that it's always enabled and performs validation when it's clicked.
Updated layout of PipelineBuilderPanel.

Updated the panel that contains the PipelineCreator to a ContentPanel with brief instructions in its header.
Widened the East region that contains this panel.
Removed pipeline-builder style and panel header.

Removed unnecessary style and panel header.
Add mask over PipelineBuilderPanel for valid Apps.

Updated PipelineBuilderPanel so that it becomes masked when an App that can be appended to the Pipeline is dragged over the panel.
This give the user more feedback that the App can't be inserted into the Pipeline and only appended to its end.
Updated the DNDListeners to handle drag start, enter, leave, and cancel events and not move events.
Removed PipelineInfoPanel from PipelineEditorPanel.

Updated PipelineBuilderPanel to expect the pipeline name and description to come from the PipelineCreator.
Increased the width of the PipelineCreator region.
core-3631 fix grammer in confirmation message"
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(cherry picked from commit b3bad88ac3268b83050ba58b7476461f2b21723b)
core-3541 add max lenghth to pipeline name field
(cherry picked from commit 422c104918a3134bca46397229e517835568ffcb)
Updated GWT version to 2.5.0 proper.
Refactored original PipelineEditorPanel into PipelineStepEditorPanel.

Added a new PipelineEditorView base class that PipelineStepEditorPanel and PipelineBuilderPanel now extend.
Added the new PipelineStepEditorPanel as a view that can be toggled with the PipelineBuilderPanel view in the new PipelineEditorPanel.
Removed the Publish button and bottom toolbar from PipelineStepEditorPanel.
Refactored PipelineAppModel and PipelineStepEditorPanel::toJson.

Updated PipelineAppModel and the toJson methods in the PipelineStep panels and PipelineStepEditorPanel to return the more simplified JSON used by the PipelineCreator.
Updated the PipelineStepEditorPanel::configure and PipelineStep panels' setData methods to parse the new JSON format.
Refactored PipelineBuilderPanel::getPublishJson into the base PipelineEditorView class, since both PipelineBuilderPanel and PipelineStepEditorPanel are now using the same Pipeline JSON.
Merge branch 'master' into pipeline-builder
Merge branch 'pipeline-builder' into gxt3-sandbox

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