Improve gltf-io and manifold-gltf (#612)

* fixed build copy for npm

* update deps

* fixed glTF validator errors

* fixed bug and Vite

* clamped color

* converted manifold-gltf to TS

* converted gltf-io to TS

* fixed TS build

* avoid usage warnings

* update MV

* clean up types

* update gltf-io API

* fixed bugs

* fixed disposal

* fixed example

* a few fixes and cleanup

Author: elalish