tilecache_seed.py --version parameter

From the mailing list:

On 24.01.2014 14:51, manel.clos at ajgirona.cat wrote:

> There is no "--version" option in tilecache_seed, see usage from Client.py
> 
> ```
>  usage = "usage: %prog <layer> [<zoom start> <zoom stop>]"
> ```

According to the README http://www.tilecache.org/docs/README.htmlfile, 
it has.

Agnar Renolen
