PyAssimp: Support for property setters? (for modifying scenes, mesh vertices, etc.)

Per [this StackOverflow comment](https://stackoverflow.com/questions/49151031/pyassimp-ignores-all-modification-before-the-export#comment88230110_49151031), and confirming by looking at this file, `pyassimp` most fields are copied, rather than referenced, into a NumPy array, and does not seem to provide property setters:
https://github.com/assimp/assimp/blob/524d8c281e78cecd810c19bc0489c57e030cb200/port/PyAssimp/pyassimp/core.py

If possible, it'd be awesome if the NumPy could reference the C arrays, if the memory can be strided and all that. (Understandably, this would be quite a bit of work!)

Discovered this after trying the same things as OP on the StackOverflow post :P

EDIT: Adding search engine keywords, 'cause why not: "mesh editing writing reexport gltf"
Added some potential alternatives to SO post.

Start by reading port/PyAssimp/pyassimp/core.py and the linked StackOverflow discussion to understand which scene and mesh fields are copied into NumPy arrays. Determine whether the relevant C arrays can be exposed safely, including striding and lifetime concerns. Done means supported scene or vertex modifications persist through export, with the behavior verified against the reported mesh-editing workflow.

Written by the indexing model from the issue text.