Added suppor for ip ranges, cidr and other improvements

• Support for ip ranges and cidr on the ignore.ip.list thanks to @safly (https://github.com/safly)
• grepcidr install requirement introduced with the support for CIDR
• New syntax supported on ignore.ip.list
  a.b.c.d/xy (CIDR format)
  a.b.c.d-e.f.g.h (IP range)
  For more details read the grepcidr man page.
• Fixed bug $CONF not found thanks to @WoozyMasta (https://github.com/WoozyMasta)
• Added unban flag -u --unban
• Added logrotate configuration file to uninstall script.
• Prioritize systemd detection on install script.