Make sure all media is up to date

Ember has quite a lot of media. However, there's a need for an overhaul of how the media and the model definitions are synchronized with what's available on the server. This task involves going through both all media in the client as well as all entity types in Cyphesis to make sure that:
1) All meshes have corresponding models
2) All entity types have corresponding models, where available. This also involves making sure that entity mapping is up to date.
3) All models are correct, and fits the server representation. This might in some cases require changes to the server definition (for example bounding boxes).
4) If there's media on the client, but no entity type on the server, investigate whether we might then need to create an entity type.