[scriptassist.pl] Move scripts to autorun directory when symlinks are not supported

I have an irssi session on which symlinks are not supported.

Whenever I update my scripts via `/scriptassist update all` and restart my session later, those updated scripts are not ran automatically at startup. Trying to do this by hand doesn't work as well:

```
/scriptassist autorun adv_windowlist.pl
>> Unable to create autorun link
```

Obviously, what's happening under the hood is:

```sh
$ pwd
/home/users/mataha/.irssi/scripts
$ ln -s adv_windowlist.pl autorun
ln: failed to create symbolic link ‘autorun/adv_windowlist.pl’: Operation not supported
```

Right now I'm using an *ad lib* bash script to move (updated) scripts manually into autorun directory whenever I perform an update, but I feel this could be integrated into `scriptassist` itself.