On Emissaries and Meshes (Idea for Mesh Cache)

So, the original idea for the _payload directory in the Emissary was to allow the initial state of meshes and whatever other assets might be needed for the Entity to operation.  Problem with that is, after the mesh moves from its initial state, that part of the Emissary file now becomes unusable dross, weighing down the file and requiring it to be transferred each time it is cached. 

I'm thinking instead, that what is needed is a separate cache database (probably in sqlite) which contains the various meshes in whichever states are needed, and to have a separate way to download them to the browser.   Basically, you'd have an Entity Id, the Mesh Id, and probably a state id (which might be simply a incrementing integer, or some other form of version).  We need a fast and efficient serialization/deserialization format for meshes.   Maybe there's a standard out there.

_payload is likely still useful for other fixed assets, like audio files or jpeg images.