daemon - Systemd and Service support, -nagios_init

Systemd based systems now function correctly and daemon assumes use of
service_name instead of nagios_init. The main rationale for the change is
how to query if the nagios service is running. Service status is pretty
expensive so what daemon does is lookup pid file if nagios_init or
service is used but "systemctl is-active nagios" on systemd based
systems.

Added a bunch of tests for the new and old functionality.

Switch was also made from internal subprocess.Popen calls to use the
pynag.Utils.runCommand which is easier to mock from a testing
standpoint.

sudo use in nagios_init is also deprecated and is a flag now, sudo=True
when creating a new daemon() instance.

All calls now populate self.stderr and self.stdout which calling
programs can utilize to determine why something broke.
Travis has no init scripts, faking
Travis has no init scripts, faking again
Make travis install nagios3 before running tests
Revert "Make travis install nagios3 before running tests"

This reverts commit f53e32ea28d41fbea6bdc9f9a0f578ab325fbe8b.
daemon - skip doctest, variable service name
daemon - remove unused modules
daemon, remove usused variable
Control - PEP8 fixes
pynag.Control better testing of new methods

Added tests to check how full paths to commands and scripts are
manipulated.
pynag.Control improve docstring
Merge pull request #132 from pynag/systemd

Systemd support and nagios_init deprecation - start your testing engines