2.18 RC1

Here's a list of some of the changes...

• Fix double-free scenario in case if duplicate interface was specified
• Separate systemd and SysV packaging
• Update fedora packaging files
• No router advertisements on tunnel interfaces
• Add nodaemon option to the manpage
• Write to stderr in non-daemonized mode
• Fixes memory leak in add_ra_options_dnssl
• Allow quoted strings in config.
• nd_opt_6co endianness fix