CKAN cleanup script... and some minor typo fixing in other parts

Solves issue #62 
Creating this README.md I think I found a typo in the README.md for MySQL cleaner. In particular, in that readme we have:

>In order to program the scheduling, create a `cygnus_crontab.txt` file. Put the following line within that file, if >wanting to execute the script every hour:
>
>    0 */1 * * * /usr/share/cygnus/mysql-cleaner.sh
>
>Now, invoke the crontab to set your cron job:
>
>    $ sudo crontab cygnus_crontab.txt
>
>You can check it has been successfully set by typing:
>
>    $ sudo crontab -l
>    0 */1 * * * /usr/share/cygnus/mysql-cleaner.sh <MySQL_host> <MySQL_user> <MySQL_password> <data_lifetime_days>

I think the first reference to /usr/share/cygnus/mysql-cleaner.sh should include parameters (as the sceond reference).