Add the normalized parameter to the InstancedBufferAttribute constructor

[jfranc]

No description provided.

[mrdoob]

Hmm, if I would have knew, I would have put the normalized parameter the third. Now we can't do that without breaking things :/

[Mugen87]

How about this:

function InstancedBufferAttribute( array, itemSize, normalized, meshPerAttribute ) {

	if ( typeof ( normalized ) === 'boolean' ) {

		BufferAttribute.call( this, array, itemSize, normalized );

	} else {

		BufferAttribute.call( this, array, itemSize );

		if ( typeof ( normalized ) === 'number' ) {

			meshPerAttribute = normalized;

			console.error( 'THREE.InstancedBufferAttribute: The constructor now expects a boolean as third parameter (normalized).' );

		}

	}

	this.meshPerAttribute = meshPerAttribute || 1;

}

This approach should be backwards compatible.