Add instructions for mosh

Since mosh is using ssh for authentication non-interactively we have to
use the AUTH_TOKEN environment variable.
Trim trailing whitespace
Fix markdown formatting.
Merge branch 'trim_trailing_whitespace' of https://github.com/simmel/authy-ssh

Conflicts:
	README.md
Improve a little the markdown formatting.

Also, corrected a couple of typos.
Request sms function now receives the authy id to send the message to.

When using multi-accounts per unix account it was trying to find a unix
user to send the message but if the user wasn't registered in the config
file then it would fail.
Thanks to Alexandre Silva for reporting this issue.
Only display banner if it is present
Bump version to 1.4
Merge remote-tracking branch 'upstream/master'

Conflicts:
	authy-ssh.sha1sum