`docopt` incorrect usage + pep8

Hi,

It seems the migration to `docopt` isn’t complete, so I made it better by changing `elif`s to `if`s in handling the command line options.
In addition, some changes in order to more completely conform to pep8 were made.

Thanks,
Júda
Hmmm, I don't have time to check it now, but there is a lot a things to do with the code. I was kind of a mess and still kinda is... 

I'll check this later. Anyway, thanks for the pull!