function Repulsion(targetPosition, force, radius, life, easing) {
      var _this;
      _this = _Attraction.call(this, targetPosition, force, radius, life, easing) || this;

      /**
       * The strength of the repulsion force
       * @type {number}
       */
      _this.force *= -1;

      /**
       * The name of the behaviour
       * @type {string}
       */
      _this.name = "Repulsion";
      return _this;
    }
Creates a new Repulsion behaviour instance

@constructor
@param {Proton.Vector2D} targetPosition - The repulsion point coordinates
@param {number} [force=100] - The strength of the repulsion force
@param {number} [radius=1000] - The radius of influence for the repulsion
@param {number} [life=Infinity] - The behaviour's life
@param {string} [easing='easeLinear'] - The behaviour's easing function