Provide appropriate wiring for remote-hosted bricks

[Daniele Lacamera]

1. Any wiring from one host to another must be prohibited - either by not showing remote socks in the socks combos, or by displaying an error during connect().

2. "Wire"s running on remote host must not be able to connect to local bricks. See 1.

3. Local "Wire"s can connect to remote host. Wire cannot start when the host is offline.
When the Wire is started:
- send a command via TCP to the host, to open a UDP socket attached to the Switch.
- Pywire the local sock and create an UDP socket, connect them together as for local cables, in PyWireThread class run() method
- when the host goes offline, PyWire must die.

[Daniele Lacamera (o-root-danielinux-net)]

Local-to-remote pywire, working prototype committed in r301