Rework key setup

[migueldeicaza]

Rather than binding a specific key per connection, treat all keys as the keys that can be suggested to the remote server, like ssh-agent.

[migueldeicaza]

This is done, but I should allow in the host editing to have an empty ssh key, but when this is the case, perhaps I should force just the use of SSH keys, and not bother prompting for a login/password?

[migueldeicaza]

Done