For both `MapToolClient.start()`, if an `IOException` is thrown we now guarantee that the state will be `Closed`. This
means the caller doesn't have to worry about cleaning up the client by calling `.close()` themselves on an object with
some indeterminate state. Similar thing for `MapToolServer.start()` - its state will be set to `Stopped` if an
`IOException` is thrown.

`MapTool.startServer()` now relies on this by catching any `IOException` from the client. In this case it stops the
server before propagating the exception. This makes sure both client and server are in a determinate state if
`startServer()` fails.

The change to `SocketServer.start()` is only to make it more clear what the state will be in case of a failure.

onComplete callbacks ow receive a flag indicating whether the handshake was successful. This allows us to bail early and
to avoid proceeding with logic that assumes a successful connection. On the disconnect side, some logic was moved around
to where it makes more sense, in particular expected disconnects resulting from `AppActions.DISCONNECT_FROM_SERVER`.

Clients are now created after their respective servers if any. This isn't a huge deal, but is more intuitive and allows
us a bit of an easier time in the client disconnect handler.

The parameters were never been filled because the server does not produce its version in the handshake message. This
could be fixed, but comes with BC concerns so I just fixed the strings for now.