replace SVG image pattern with file-processor

The filter replace value of image attr ***xlink:href*** to the new rev img filenames

Example:

```html
<svg width="600" height="400" >
  <defs>
    <pattern id="grain" width="406" height="634" patternUnits="userSpaceOnUse">
      <image x="0" y="0"  width="406" height="634" xlink:href="images/grain.jpg"></image>
    </pattern>
    ...
  </defs>
  ...
</svg>
```

To replaced:

```html
<svg width="600" height="400" >
  <defs>
    <pattern id="grain" width="406" height="634" patternUnits="userSpaceOnUse">
      <image x="0" y="0"  width="406" height="634" xlink:href="images/6b0e572d.grain.jpg"></image>
    </pattern>
    ...
  </defs>
  ...
</svg>
```