Test with USD Compliance Checker.

[elliotcmorris]

USD has a compliance checker in its source : https://github.com/PixarAnimationStudios/USD/blob/0c7b9a95f155c221ff7df9270a39a52e3b23af8b/pxr/usd/usdUtils/complianceChecker.py

We should investigate if appropriate and run the compliance checker against the plugin as a test at some point.