Add a tip for the bold and lazy to the docs

A slightly bolder and more lazy tip that I'm not including is that you
can just do:

  killall sshd

Unless you are foolhardily running as root, in which case that will
lock you out of your server. Let's not encourage people to be too
heavy-handed.

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Add section about Mosh to the docs

This commit adds some tips on getting Mosh, SSH and Clipper playing
nicely together. I include the section about the various `Control*`
settings because they are a complicating variable which needs to be
dealt with.

(In general, the `Control*` settings are a great time saver, but they
can make trouble-shooting difficult and we can simplify the business of
setting up a "pure-forwarder" for use with Mosh by keeping them out of
the picture.)

Signed-off-by: Wincent Colaiuta <win@wincent.com>