Allow optimizer to skip node hierarchies
Morrowind assets have the "sgokeep" string data, but apparently it's only used by external tools, the engine itself does mo optimizing to begin with.
We should allow important nodes to be skipped by optimizer entirely. Relying on just the string data is not enough, though we can use it as a hint. This is because some assets are cleaned by modders (since its not useful to engine).
Right now we have no such granularity in the optimizer, simply a hardcoded set of files are skipped. At very least particle system emitters should not be skipped.
Edited by Cody Glassman