mosh-client: Print exceptions after the client is shut down

Otherwise the printed exception may be immediately hidden when the
terminal exits alternate screen mode.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Connection: Store the port number as a string

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Connection: Move socket creation out of setup

Once we support IPv6, we won’t be able to create a socket until we
know which address family to use.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Connection: Support IPv6 addresses

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
scripts/mosh: Let IO::Socket resolve the hostname

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
scripts/mosh: Add -6 option to connect with IPv6

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
debian/control: Recommend IO::Socket::IP

This is optional, but needed for IPv6 support.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Implement xterm mouse mode
Implement xterm extended mouse mode
xterm extended fix
Implement vt100 mouse mode (1000)

(closes #461)