Struct Support

[Shadorain]

Summary

Add asset-derive support to Struct data types as well instead of only enums.

Idea

I realized with the trait addition #4 , it made having struct's being asset's themselves quite simple.
Simply derive the Asset trait on it and the struct itself will have its own filename and asset to fetch.
It is limitted to just one asset (unless we do fields in the future too) but it wouldn't be restricting to just enums.