Cycles: add Displacement node.

This converts object space height to world space displacement, to be
linked to the new vector displacement material output.

Differential Revision: https://developer.blender.org/D3015

release/scripts/startup/nodeitems_builtins.py

@@ -271,6 +271,7 @@ shader_node_categories = [
     ShaderNewNodeCategory("SH_NEW_OP_VECTOR", "Vector", items=[
         NodeItem("ShaderNodeMapping"),
         NodeItem("ShaderNodeBump"),
+        NodeItem("ShaderNodeDisplacement"),
         NodeItem("ShaderNodeNormalMap"),
         NodeItem("ShaderNodeNormal"),
         NodeItem("ShaderNodeVectorCurve"),