instance-ssh() takes piped input and connects to multiple instances
instance-ssh() takes piped input and connects to multiple instances

Very excited to have worked out how to reattach keyboard input
to a function with piped input.

```
$ instances | grep bastion | instance-ssh
```

This will ssh to all the bastions (in a loop).

jonhiggs/bash-my-aws,azrupani/bash-my-aws,realestate-com-au/bash-my-aws,limed/bash-my-aws