Updated `.travis.yml': set CI runtime username

The site username has been over-ridden via the environment to `travis'
to allow for ssh unit tests.
Updated `module/dns': speed, update

Updates:

    If there is a hosts file entry for a qdn or shn, (as opposed to
    just fqdn), then there was a gap in how `:dns:inspect.csv'
    function operated, and the resolution would be tagged `ext',
    instead of `qdn'.  This patch fixes that problem.

    Updated the `docstring' example of how the `:dns:lookup.csv'
    function can-be/should-be used.

Speed:

    It appears as though `getent host' will try and perform a dns
    resolution even if files is first in nsswitch.conf.  The
    workaround it to issue no `key' to the command, and parse the
    output of `getent host' instead which significantly improves name
    resoltion by removing the extraneous dns resolutions.
... share/unit/tests/dns-static.sh
Updated `module/remote': cleanup, simplification

Updated (mostly simplified) the code based on the new `dns' module.

Removed the cfrun function which was out-of-place, and moved some
general ssh options to the top of the file.

Added missing dependency on the `vault' module.
Added `module/remote' unit tests: issue 13
Updated `README.md'