Mod: hacked manage.py so that the settings file can be changed.

manage.py still uses the --settings option but only for setting
the module name (site folder) where the desire settings.py is.
After the value has been used, the --settings=foo option is
altogether removed from sys.argv so as not to interfere with
normal operations.

Did this because Django keeps on ranting about the SECRET_KEY
needing a value, but there's a value in the settings.py. So,
dirty hack might be dirty.