function Vec3(x,y,z){
    /**
     * @property x
     * @type {Number}
     */
    this.x = x||0.0;

    /**
     * @property y
     * @type {Number}
     */
    this.y = y||0.0;

    /**
     * @property z
     * @type {Number}
     */
    this.z = z||0.0;
}
3-dimensional vector
@class Vec3
@constructor
@param {Number} x
@param {Number} y
@param {Number} z
@author schteppe
@example
    var v = new Vec3(1, 2, 3);
    console.log('x=' + v.x); // x=1