Workflow editor backbonification - add NodeView.
Including unit tests.
Workflow editor backbonification - add DataInputView.
Workflow editor backbonification - add view for output callout.
Workflow editor backbonification - add view for output data view.
Workflow editor backbonification - add InputTerminalView.
Add unit tests for new view.
Workflow editor backbonification - add OutputTerminalView.
Add unit tests for OutputTerminalView.
Workflow editor backbonification - InputTerminalView to Backbone.View event binding.
Workflow editor backbonification - OutputTerminalView to Backbone.View event binding.
Workflow editor backbonification - move terminal presentation logic from NodeView to DataInputView.
Workflow editor backbonification - move terminal presentation logic from NodeView to DataOutputView.
Workflow editor backbonification - refactor some update_field_data presentation logic into NodeView.
Workflow editor backbonification - make Node a model.
Workflow editor backbonification - make Terminal classes into models.
Workflow editor backbonification - reposition views to more appropriate part of file.
Merge pull request #363.

Was previously declined so that pull request #370 could be resolved first - but upon actually inspecting #370 I don't think these will conflict in anyway.