3D Texture minor update

[takahirox]

See #14530 (review) and #14530 (review)

[mrdoob]

Thanks!

[mrdoob]

I think I would also remove most of the parameters and leave the constructor like this:

function Texture3D( data, width, height, depth )

[takahirox]

And we add .setXXX( value ) methods instead?

[mrdoob]

Yes, and these can be set in Texture directly. But doesn't have to be done now, the user can always do...

var texture = new THREE.Texture3D( ... );
texture.anisotropy = 16;

I just want to avoid continuing the parameters mess in this new class.

[takahirox]

OK, so let's do function Texture3D( data, width, height, depth ) so far. And let's add setXXX() methods when we add setXXX() methods to regular Textures.

[mrdoob]

Sounds good!