It posible add ?v=xx preffix to generated css

[Bogdaan]

When i generate new sprite - old users fetch "icons.png" from local cache
It posible generate version preffix to output background-image?

[twolfson]

The simplest way for a numeric based prefix would be to generate a timestamp as part of the filename:

dest: 'icons?v=' + Date.now() + '.png'

If you are interested in using an MD5 hash instead of a timestamp, please see #27