Remove component types that are not present in GLTF spec
Remove component types that are not present in GLTF spec

GLTF spec says that component type declares the type of a scalar
component, and type - vec2/etc. - declares the component count.

All vector-like component types were unused and potentially confusing to
the user.

jkuhlmann/cgltf,jkuhlmann/cgltf,jkuhlmann/cgltf