v0.2.0 Terrain import, full hierachy, merged meshes and joints, plus bugfixes

v0.2.0

Pure-Python rewrite — no external binary needed.
The 16 MB i3dToObjx.exe and the .objx detour are gone, replaced by a
pure-Python .i3d.shapes decoder (ported from I3DShapesTool, MIT).

Added

• Pure-Python .i3d.shapes decoder
• Full hierarchy, transforms, materials, multi-UV and vertex colors
• Custom properties on objects/materials for re-export fidelity to the Giants Editor
• Skin / Merge Group / MergeChildren import
• Spline decoder
• Bone rotation + translation for skin weights
• Terrain import (proof of concept)

Fixed

• FS22 shapes decoder: subset padding + pre-triangle padding
• Axis roundtrip: rotation_euler preserved instead of baked; Y-up → Z-up conversion; light/camera special case
• Pink-material bug, object-space UV, invisible-GE toggle

Changed

• Removed bundled i3dToObjx.exe and objx_parser.py
• UX refactor of the import dialog