An upgrade for the asset importer

Some features/improvements I would love to see in the asset importer:

• Make it possible to create custom doors by selecting the internal object that needs to rotate when you click it
• Make it possible to mark surfaces of which you want to be able to change the color.
• better automatic colliders (per internal object instead of one global one)
• when importing an object, import it on the same place on the grid as it is in the file. Now it is always centered, which makes it difficult when creating modular pieces.

Might not be a popular feature request, because not everyone uses the asset importer, but it would improve my experience a lot.