Sender - log to STDOUT only
Sender - replace _"_ with _'_ where appropriate
Sender - turn it into runit service

Commit turns Nagios Sender into runit service. Config file is therefore removed
and the most of parameters are set via arguments or ENV variables.
Sender - require ENV variables in main(), not global

Require ENV variables in main() and not in global scope.
Sender - fix send_interval -> interval
Sender - fix reference to non-existing glob vars

Commit fixes references to global variables which no longer exist, because they
were moved into main in previous commit.
Sender - fix signal handler

I don't want to use args/kwars here, so...
Sender - remove trailing wspace
Sender - add some debug output
Sender - we don't want sys.exit() here!
Sender - actually, block on queue
Sender - give more insight into what's going on
Configurator - fix logging
Configurator - utilize services when ensuring host definitions

Utilize services when ensuring host definitions. This very, very specific of
CoreOS which doesn't have config sender, but might be useful elsewhere.
Configurator - set logging level to INFO
Configurator - fix ensure_host_definition()

Fix an invalid dictionary being passed to write_definition() which resulted in
Py objects being written into config rather than Nagios config structure.
Sender - add dependency on python-requests=2.0.0

I've noticed connections are being left open by Sender. This is caused by 'bug'
in python-requests shipped with Debian, resp 0.12.1.
I've also added call to rsp.close() which returns/releases connection to
connection pool.
Configurator - split run() into two

Split code in run() into two in order to be able to re-use some of the code.
Configurator - clean up Python coding style
Receiver - clean up Python coding style