Panda3d-gltf

Converter
* Reparent GeomNodes to physics nodes
* Generate quad CollisionPolygons where possible
* Use correct array type for AnimChannelScalarTable.set_table()
* Allow for `byteOffset` to be optional in `accessor` and `bufferView`
* Set correct contents on transform_weight/_index columns
* Fix import of padded vertex columns
* Support `application/gltf-buffer` for uri
* Force normalization of joint weights
* Fix morph targets when mesh does not specify default weights
* Fix morph targets when neither weights nor targetNames is given
* Use new Panda3D 1.10.8 M_emission mode
* Make sure texture modes are set for all textures

Converter
* Fix objects without emission texture being invisible with alpha on
* Fix punctual light direction in Y-up scenes (81)
* Support KHR_texture_transform
* Generate flat normals when no normals are present
* Support spotlight falloff
* Fix emission not working without emissiveTexture in simplepbr

Viewer
* Don't create a PointLight if the model already has a light
* When parenting lights to render, maintain absolute transform

Converter
* Add option to save animations to separate files
* This is can be accessed via the CLI using `--animations separate`

Converter
* Disable back-face culling on double-sided materials
* **Note:** Blender materials are double-sided by default, so this may break some currently working setups
* Fix black objects when using fix-function pipeline or auto-shader along with PBR materials
* Allow empty scenes without Geoms
* Fix component sizes in mesh data buffers

Converter
* Add texture and material attribs to fallback RenderState
* Add option to convert PBR glTF materials to "legacy" materials
* This is best effort and data *will* be lost
* Exposed in `GltfSettings` as `legacy_materials` (defaults to `False`)
* Exposed in `gltf2bam` as `--legacy-materials` flag

Converter
* Add support for joint/bone parents
* Add support for PANDA3D_physics_collision_shapes extension (includes new intangible setting)
* Fix errors when using double-precision builds of Panda3D
* Fix ZeroDivisionError when loading single-frame animations
* Fix loading meshes with no indices
* Fix loading model tangents on Z-up files
* Fix generating tangents on Z-up files
* Fix the sign on generated bi-tangents