WIP: Support gpu and other queues

This PR is not finished yet :p. We need to discuss about the pbs_generator class.

Fixed #34
From `man qsub`
```
       -N name Declares a name for the job.  The name specified may be  up  to
               and  including  15  characters  in  length.  It must consist of
               printable, non white space characters with the first  character
               alphabetic.

               If  the  -N  option  is not specified, the job name will be the
               base name of the job script file specified on the command line.
               If  no  script  file name was specified and the script was read
               from the standard input, then the  job  name  will  be  set  to
               STDIN.
```