Changepassword command

Because Deis doesn't support interactive shells (yet) we cannot run `createsuperuser` without `--noinput` and therefore we cannot set the superuser password. Similarly for `changepassword` command. This package adds a `changepassword2` command which reads the password from the command line. To create a user

```
deis run -- ./manage.py createsuperuser --username foo --email foo@example.com --noinput
deis run -- ./manage.py changepassword2 foo 123
```

The alternative is to directly ssh into a coreos host and run manage cmds but I'd like to avoid that and instead provide a deis way to do this. What do you think @jgmize?