function createTransformFeedbackInfo(gl, program) {
	    var info = {};
	    var numVaryings = gl.getProgramParameter(program, gl.TRANSFORM_FEEDBACK_VARYINGS);
	    for (var ii = 0; ii < numVaryings; ++ii) {
	      var varying = gl.getTransformFeedbackVarying(program, ii);
	      info[varying.name] = {
	        index: ii,
	        type: varying.type,
	        size: varying.size
	      };
	    }
	    return info;
	  }
Create TransformFeedbackInfo for passing to bind/unbindTransformFeedbackInfo.
@param {WebGLRenderingContext} gl The WebGLRenderingContext to use.
@param {WebGLProgram} program an existing WebGLProgram.
@return {Object<string, module:twgl.TransformFeedbackInfo>}
@memberOf module:twgl