Lorem Pixel for prototype images

Following up on this [feature request](http://webessentials.uservoice.com/forums/140520-general/suggestions/3997568-zencoding-add-lorempixel-for-dummy-images), I have implemented [LoremPixel](http://lorempixel.com/) for zencoding. The LoremPixel supports user-friendly URLs to request images of various dimensions ranging from 0-1920 for both width and height. Other configurations are: 

- specify one of these categories; abstract, animals, business, cats, city, food, night, life, fashion, people, nature, sports, technics and transport. 

- Gray scale images with second URL component be 'g'.

- Text to be printed on a side of the image.

- Ten pictures for each configuration

For an instance:

    http://lorempixel.com/400/200
    http://lorempixel.com/g/400/200
    http://lorempixel.com/400/200/sports
    http://lorempixel.com/400/200/sports/1
    http://lorempixel.com/400/200/sports/Dummy-Text
    http://lorempixel.com/400/200/sports/1/Dummy-Text

With this addition, the equivalent zencoding commands would be:

    pix-400x200
    pix-g-400x200
    pix-400x200
    pix-400x200-sports
    pix-400x200-sports // a random number from 1-10 shall be appended with the URL
                      // to select from one of the ten images provided for each category)
    pix-400x200-sports-Dummy-Text
    pix-400x200-sports-Dummy-Text // random number from 1-10 to be appended automagically


Furthermore, if the Width and Height exceed 1920 bound (`pix-g-2020-3400-animals-LoremIpsum`), the modulus of 1920 would be applied on both Width and Height. In this example the resultant image source would be: 

http://lorempixel.com/g/100/1480/animals/LoremIpsum/

Please review the feature and add it to WebEssentials 2013. It would be rather convenient, if we are able to use this feature of zencoding in .css files as well as the inline CSS.

Thanks.