1daa9fbbed
This is needed to support deeply nested material property groups, it just makes the serialization code a lot simpler than trying to support nested groups in the .material file. It also makes the file more readable and easier to search all files for particular properties. I also updated MaterialSourceData to hide the property values behind a clean API. Signed-off-by: santorac <55155825+santorac@users.noreply.github.com>