code: function ColorMatrixFilter()
  {
      core.AbstractFilter.call(this,
          // vertex shader
          null,
          // fragment shader
          fs.readFileSync(__dirname + '/colorMatrix.frag', 'utf8'),
          // custom uniforms
          {
              m: { type: '1fv', value: [1, 0, 0, 0, 0,
                                      0, 1, 0, 0, 0,
                                      0, 0, 1, 0, 0,
                                      0, 0, 0, 1, 0,
                                      0, 0, 0, 0, 1] },
          }
      );
  }
docs: The ColorMatrixFilter class lets you apply a 5x5 matrix transformation on the RGBA
  color and alpha values of every pixel on your displayObject to produce a result
  with a new set of RGBA color and alpha values. It's pretty powerful!
  
  ```js
  var colorMatrix = new PIXI.ColorMatrixFilter();
  container.filters = [colorMatrix];
  colorMatrix.contrast(2);
  ```
  @author Clément Chenebault <clement@goodboydigital.com>
  @class
  @extends AbstractFilter
  @memberof PIXI.filters