* FIX format parameter
To be able to print files in raw format it's needed to set this parameter.
Previous code was not able to print raw files, but it didn't get error because 'format' used on line 107 is assumed as a format funtion, because format parameter was not on this scope.
* FIX pep8
* [IMP] Updated unit tests
* [FIX] Fixed renamed attributes
* [FIX] Remove deleted fields
* [IMP] Add printing.server and printing.job models
* [IMP] Allow to cancel all jobs, enable, and disable printers
* [IMP] Split the cups part of print_document into a new print_file method
* [IMP] Updated cron job to run the action_update_jobs method
* [ADD] Add a migration script to create a printing server from configuration