code: function(sx, sy) {
              var m11 = this.m[0] + this.m[2] * sy;
              var m12 = this.m[1] + this.m[3] * sy;
              var m21 = this.m[2] + this.m[0] * sx;
              var m22 = this.m[3] + this.m[1] * sx;
              this.m[0] = m11;
              this.m[1] = m12;
              this.m[2] = m21;
              this.m[3] = m22;
              return this;
           }
docs: Apply skew
  @method
  @memberof Kinetic.Transform.prototype
  @param {Number} sx
  @param {Number} sy
  @returns {Kinetic.Transform}