code: function OutlineFilter(thickness, color) {
      thickness = thickness || 1;
      PIXI.Filter.call(this,
          // vertex shader
          // vertex shader
          glslify('./outline.vert'),
          // fragment shader
          glslify('./outline.frag').replace(/%THICKNESS%/gi, (1.0 / thickness).toFixed(7))
      );
  
      this.uniforms.thickness = thickness;
      this.uniforms.outlineColor = new Float32Array([0, 0, 0, 1]);
      if (color) {
          this.color = color;
      }
  }
docs: OutlineFilter, originally by mishaa
  http://www.html5gamedevs.com/topic/10640-outline-a-sprite-change-certain-colors/?p=69966
  http://codepen.io/mishaa/pen/emGNRB
  
  @class
  @param thickness {number} The tickness of the outline. Make it 2 times more for resolution 2
  @param color {number} The color of the glow.
  
  @example
  someSprite.shader = new OutlineFilter(9, 0xFF0000);