fades --help does not show -x in the "usage:" summary

[nessita]

nessita@miro:~$ fades --help
usage:
fades [-h] [-V] [-v] [-q] [-i] [-d DEPENDENCY] [-r REQUIREMENT] [-p PYTHON]
[child_program [child_options]]

[facundobatista]

There is a mismatch between the parameters shown in the "usage" with the rest of the help (where -x is shown), we need to solve that mismatch (and check the man, now that we're on this...)