Lintian, systemd, ufw, and upstart enhancements for Debian and Ubuntu

This branch, which depends on the SoftEtherVPN/SoftEtherVPN#50 autotools branch, enhances SoftEther with DPM conforming:

* Lintian fixes.
* Systemd integration.
* Upstart integration.
* UFW firewall rules.

Debian Wheezy and ARM platform support are notably improved.