Initial nodedef comparison script (AcademySoftwareFoundation#2723)

This changelist adds an initial nodedef comparison script to MaterialX, allowing a user to compare node definitions between a data library document (e.g. stdlib_defs.mtlx) and a specification document (e.g. MaterialX.StandardNodes.md), reporting any differences between the two in their supported node sets, typed node signatures, and default values.

The new script builds upon the recent node formatting improvements proposed by the AOUSD Materials Working Group, which greatly increased the accessibility of the MaterialX specification documents to machine parsing and analysis.

GitHub CI additionally calls the nodedef comparison script on each commit to MaterialX, providing a trackable history of the alignment between data libraries and the specification.

Author: jstone-lucasfilm

.github/workflows/main.yml

@@ -232,6 +232,7 @@ jobs:
       run: |
         python MaterialXTest/main.py
         python MaterialXTest/genshader.py
+        python Scripts/comparenodedefs.py
         python Scripts/creatematerial.py ../resources/Materials/Examples/StandardSurface/chess_set --texturePrefix chessboard --shadingModel standard_surface
         python Scripts/creatematerial.py ../resources/Materials/Examples/GltfPbr/boombox --shadingModel gltf_pbr
         python Scripts/mxformat.py ../resources/Materials/TestSuite/stdlib/upgrade --yes --upgrade