function initialNormal1(lastBinormal) {
		// fixed start binormal. Has dangers of 0 vectors
		normals[ 0 ] = new THREE.Vector3();
		binormals[ 0 ] = new THREE.Vector3();
		if (lastBinormal===undefined) lastBinormal = new THREE.Vector3( 0, 0, 1 );
		normals[ 0 ].cross( lastBinormal, tangents[ 0 ] ).normalize();
		binormals[ 0 ].cross( tangents[ 0 ], normals[ 0 ] ).normalize();
	}
@author WestLangley / https://github.com/WestLangley
@author zz85 / https://github.com/zz85
@author miningold / https://github.com/miningold

Modified from the TorusKnotGeometry by @oosmoxiecode

Creates a tube which extrudes along a 3d spline

Uses parallel transport frames as described in
http://www.cs.indiana.edu/pub/techreports/TR425.pdf