mosh perl wrapper: New option --bind-ip={ssh|IP}

Allow overriding the switch passed to mosh-server from -s to -i IP.

Signed-off-by: Philipp Haselwarter <philipp@haselwarter.org>
Rename --bind-ip to --bind-server, add =ANY option, add error checking.

Closes #415.
mosh-client: Make terminal escape character configurable

Uses environment variable MOSH_ESCAPE_KEY. Defaults to current Ctrl-^
which is somewhat problematic for many non-US keyboards.

Signed-off-by: Timo J. Rinne <tri@iki.fi>

Closes #425. Closes #215.
Get rid of obsolete DM-Upload-Allowed field