TextureNode: Support to sampler and texture property output

[sunag]

Usage:

const texNode = new TextureNode( texture );
const uvNode = new UVNode();

material.colorNode = new FunctionNode(
`vec3( texture2D A, sampler B, vec2 uv ) {

	return texture( sampler2D( A, B ), uv ).xyz;

}`).call({
	A: texNode,
	B: texNode,
	uv: uvNode
});

[mrdoob]

Thanks!