Resource type(s) affected: MDL0

Bug description: When primitives in a polygon are added or removed, the changes are not saved. When the file is reopened, all primitives are still in place as if nothing had changed.

Steps taken to reproduce bug: 1. Open a PAC file for a character. 2. Open ModelData[0] > 3DModels(N4WR) > Fit______00 > Polygons > polygon##. 3. Delete all primitives. This causes the polygon to not appear in the model preview. 4. Save file. 5. Reopen and recheck modified polygon.

Additional comments: Is something restoring the deleted primitives? Or should I be doing something else to remove the polygon in question (Issue #16)?