Gltf-blender-io: All export formats are embedding texture buffers

[dsinni]

It appears that all export format options, including JSON (.gltf + .bin + textures), are embedding texture buffers in the .gltf or .bin file, even when the textures are exported separately and called externally.

I'd mostly expect the buffers to be embedded for .glb, but there doesn't appear to be a way to _not_ embed them in .gltf or .bin.

My guess is that the now removed Embed buffers option might now be automatically defaulting to true regardless of whether or not the buffers are used, but you folks would know better than I.

[donmccurdy]

Hm, yeah textures were meant to be separate for the JSON (.gltf + .bin + textures) option, and embedded in the other two. Sounds like a bug in my earlier PR.

[ghost]

Just for documentation purposes: Not only do both gltf variants export image data twice (as image file and as part of the binary buffer), but they also reference both representations in the json (see below).

{
    "bufferView" : 4,
    "mimeType" : "image/png",
    "name" : "UVdark.tga",
    "uri" : "UVdark.png"
}

[julienduroure]

Is now merge in blender 2.8. Should be available in next build