AvatarSurfaceShaderSelfOccluding.Shader has been locking up Unity on import. I have actually reported this over the last 3 builds. Please pull this shader.
My experience is that it isn't really locked up at this point, just that it takes a really, really long time to compile! Exceptionally long! Run task manager and I think you will see UnityShaderCompiler.exe taking 100% of one of your CPU cores. It should eventually finish.
I can confirm this is NOT fixed. I tried this just now with Utils 1.22, Unity 2017.2.0f3, and it still hangs on AvatarSurfaceShaderSelfOccluding.Shader