Add ability to pass TextureAtlas instance or textureLoader parameter in spine loader metadata

[f0nar]

Now we can pass only raw atlas file content to spine loader

spine/packages/loader-base/src/SpineLoaderAbstract.ts

Line 106 in bda2e19

if (textAtlas) {

It would be awesome to add additional parameter as textureAtlas (or at least textureLoader that will be passed to TextureAtlas constructor).

[f0nar]

I missed spineAtlas option. Thanks