Updated `share/unit/citm': dependency installation

The code for calculating what to install for each module is much
simpler now, a little more elegant, but more importantly - easier
to maintain.
Updated `README.md': added rb, py, pl, and xplm

The `.travis.yml' has been updated to know about (but ignore failure
of (for now)) the new modules, since unit-testing is incomplete.
module/xplm: PASS even when FAILed; fixed
Unit test `xplm' added: nima/site#34
Updated `module/py': doc

Added some docs on package requirements.
Updated `module/ldap': retrospective updates

Much has changed since this module was last tested, and this commit
get this module re-aligned with what is current.
Updated `module/ng': retrospective updates

Much has changed since this module was last tested, and this commit
get this module re-aligned with what is current.
New `libexec/ssh': rewrite

The existing python/paramiko ssh interface has been rewritten in ruby
with net-ssh and friends.  Seems to be a little more reliable and less
annoying to use.

Also the python init file no longer needs to do any magic as pyenv has
since been introduced and handles all the work.
... module/xplm.sh
... module/mongo.sh