Fix tests

Simplify json::animation module

Simplify json::buffer module

Simpify json::camera module

Simpify json::extensions::scene module

Simpify json::material module

Simplify json::mesh module

Simplify json::mesh module

Simplify json::texture module

Remove json::validation::Checked enum

Replace unnecessary macro

Merge gltf-json crate into gltf crate

Simplify json::camera module some more

Add stub wrapper code

Trial generating wrapper code

Replace Void type with IgnoredAny

Remove unused Primitive type

Add wrap_indexed extension

Remove unnecessary const

Add custom (de)serialization macros

Remove accessor extensions

Remove animation extensions

Remove asset extensions

Remove buffer extensions

Remove image extensions

Remove skin extensions

Insert serde attributes automatically for Option

Insert serde attributes automatically for Vec

Test and fix auto camel case fields

Add tests for gltf(extension) attribute

Fix doc test builds

Temporarily remove extras feature

Refactor asset

Temporarily remove names feature

Refactor buffer

Insert serde attributes automatically for bool

Refactor accessor

Refactor animation

Refactor camera

Refactor image

Add default field attribute and derive macro

Refactor material

Refactor scene and root

Refactor texture

Refactor material and mesh

Refactor skin

Remove re-exports of serde_json functions

Refactor remaining modules

The giant hoist

Move Wrap trait into its own module

Refactor lib.rs

Implement Index and IndexMut for Root

Test camera projection

Rename accessor::Type as AttributeType

Remove leftovers

Add fallback for unrecognized extensions

Refactor import

* Replace `buffer::Stride` with `usize`
* Avoid serializing `buffer::View::offset`

Additional changes:

* Rename validate_hook as validate
* Allow `#[gltf(validate = "...")]` to be applied to fields
* Remove remaining gltf-json code
* Document `gltf_derive::Default` macro
* Document `gltf_derive::Validate` hook