shoes-off.el (shoes-off-start-session): Permit users to configure encryption
shoes-off.el: Allow per bouncer port configuration

* shoes-off.el (shoes-off-server-port shoes-off-start): For more consistency,
`shoes-off-server-port' is now an integer.
(shoes-off-config shoes-off-start-session): Permit to configure the port
per bouncer.
shoes-off.el: Add an option to customize the host

* shoes-off.el (shoes-off-server-host): Default host for all bouncers
(possibly customizable per bouncer in `shoes-off-config').
(shoes-off-config shoes-off-start-session): Per bouncer configuration of
the host.
(shoes-off/make-server shoes-off-start/host-history shoes-off-start): Add
the host as a new argument.
shoes-off.el (shoes-off-start): Minor fixes

- INITIAL-VALUE doesn't work as I expected.
- `read-from-minibuffer' returns a string and we need to convert "nil" to
  nil.
shoes-off.el (shoes-off-stop): Set the variable holding the process to nil once it has been deleted and don't kill a dead process