Some nodes, like Combine Color or the math nodes, label sockets
differently depending on the mode to be more descriptive.
`uiTemplateNodeView` now also uses this dynamic label rather than the
socket's name for labeling in the UI so the shown labels always match
the ones on the node itself.
Reviewed By: Hans Goudey
Differential Revision: http://developer.blender.org/D16563
b75946bcb6